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Mit einem Schimmelpilz die Welt retten

- VON THIEMO HEEG

- -AKTUALISIERT AM -08:34

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Bekannt wurde Tim Fronzek als Mitgründer der bekannten Internet-Handelsplattform Rebuy. Mit seinem neuen Start-up Nosh Bio hat er noch viel größere Pläne.

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4 Min.

Ortstermin im Berliner Technologiepark Adlershof, dem größten seiner Art in Deutschland. Hier residiert ein verheißungsvolles Start-up neben dem nächsten. Wer Tim Fronzeks Firma Nosh Bio finden will, muss ein wenig suchen. Keine großen Schilder weisen auf die Revolution hin, die das Unternehmen plant. Ein paar schmucklose Gänge, ein Büro, ein kleines Labor mit Rumpelkammer-Charme. Das war’s. Aber in den Augen des Gründers glänzt die Begeisterung.

Thiemo Heeg

Redakteur in der Wirtschaft.

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Der Klimawandel gehört zu seinen größten Sorgen. Und das erscheint nicht nur so dahergesagt. Die Frage, wie sich die klimaschädlichen Emissionen am effektivsten reduzieren lassen, treibt Fronzek glaubhaft um. Nach umfangreichen Recherchen lautet seine Antwort: mit Änderungen in der Ernährung. Vor allem weniger Fleisch bringe viel. Und da glaubt Tim Fronzek einen wunderbaren Schlüssel in der Hand zu halten. Mit einem Schimmelpilz will er die Welt retten. So großspurig würde das der zurückhaltend auftretende 43-Jährige nicht formulieren. Er ist kein windiger Verkäufer. Aber eine Spore Wahrheit steckt doch dahinter.

Kaum von echtem Fleisch zu unterscheiden

Nach ein paar Monaten Grundlagenarbeit ist Nosh dabei, erste Erfolge einzufahren. Auf der Anuga, der größten Ernährungsmesse der Welt, bekam Anfang Oktober in Köln erstmals eine größere Menge Menschen zu verkosten, womit Nosh Bio bald sehr viele beglücken will: fleischloses Fleisch, das von echtem kaum zu unterscheiden ist. Mehr als 96 Prozent von gut 2000 Testern fanden, das Produkt könne man weiterempfehlen. Im Berliner Nosh-Büro steht eine übermannsgroße Werbetafel. Ein Foto zeigt einen Teller, auf dem fünf saftige vermeintliche Fleischstücke lecker drapiert sind. Neben der Tafel kommt Fronzek argumentativ schnell in Fahrt. Knapp 30 Prozent aller globalen Treibhausgasemissionen verursache die Nahrungsmittelindustrie, rechnet er vor. Haupttreiber dabei sei die industrielle Massentierhaltung.

Keine Frage: Solche Erkenntnisse sind nicht neu. Sie rufen immer mehr Hersteller und immer mehr Kunden auf den Plan. Vegane Alternativen zu Fleisch haben Konjunktur. Doch deren Qualität ist längst nicht so, wie sie sein sollte, glaubt Fronzek: „Alles, was ich an sensorischen Eigenschaften wahrnehme, wie das Mundgefühl, ist weit weg von tierischen Produkten und nicht wirklich ansprechend.“ Dazu kommen die vielen Zusatzstoffe, die nötig sind, um Nichtfleisch wie Fleisch erscheinen zu lassen: künstliche Stärken oder das Tapetenkleister-Bindemittel Methylcellulose. In einer ihrer ersten Präsentationen stellten die Nosh-Bio-Leute die Inhaltsstoffe eines pflanzlichen Burgers denen einer Bodylotion von Nivea gegenüber. „Es war schwer zu erkennen, welches Label für die Körperpflege war und welches fürs Essen“, so Fronzek.

Ein Pilz für Sake und Miso - und noch viel mehr

Mit einem Fadenpilz will Nosh Bio das Problem lösen. Der Koji-Pilz mit dem lateinischen Namen Aspergillus oryzae wird in der japanischen Küche seit Langem zum Fermentieren verwendet, unter anderem für die Produktion von Sake und Miso-Paste. Nosh lässt den Pilz in einem flüssigen Nährmedium wachsen. Daraus ergibt sich eine Struktur, die tierischem Muskelgewebe sehr ähnlich ist, wie Fronzek erläutert. Gut geeignet, um chemische Bindemittel zu ersetzen. Zudem handele es sich bei Koji um einen der am besten erforschten Fadenpilze überhaupt: sofort vermarktbar ohne Zulassung und billig zu produzieren.

„Ich sage immer: Die Kunst, ein Unternehmen zu gründen, besteht darin, dass man mit den wenigen Erfolgen, die man generiert, die vielen Misserfolge positiv ausgleicht.“ Sätze wie dieser zeigen: Tim Fronzek ist gewiss ein Idealist, mehr aber noch ein Realist. Das mag auch zu seinem ersten großen unternehmerischen Erfolg beigetragen haben. Aus der Uni heraus startete er kurz nach der Jahrtausendwende gemeinsam mit Freunden ein Onlinegebrauchtwarengeschäft, das sich auf Spiele und Software konzentrierte. Über die Jahre entwickelte sich daraus eine der größten europäischen An- und Verkaufsplattformen für Elektronik, Bücher und Medien. Gerade hat Rebuy mit mehr als 600 Mitarbeitern die Umsatzmarke von 200 Millionen Euro geknackt.

Der gebürtige Wiesbadener ist jedoch kein Mensch, den es bis zur Rente am selben Schreibtisch hält. „Ich hatte immer die Idee, noch etwas anderes zu gründen.“ 2019 reifte die Erkenntnis: ein guter Moment, zu gehen. Zumal Ko-Gründer Lawrence Leuschner schon zuvor ausgestiegen war und mit der E-Scooter-Neugründung Tier Mobility für nachhaltigen Verkehr und damit gegen den Klimawandel zu arbeiten versuchte.

Von Schweinesteaks bis zu Fischstäbchen

Fronzek versucht das Gleiche jetzt über die Ernährungsbranche. Im Gegensatz zu Rebuy setzt er diesmal auf den Faktor B2B statt auf B2C. Das heißt: Als Kunden stehen nicht Privatkunden im Fokus, sondern Unternehmen, die schon selbst Fleischlosmarken aufgebaut haben. Für sie sei der Inhaltsstoff interessant, den Nosh als Pulver liefern will und der als Bindemittel und Stabilisator in deren eigenen Produkten fungieren soll – natürlich, ohne viel Energieeinsatz hergestellt und gesund, mit 40 Prozent Proteingehalt im Trockengewicht, wirbt Fronzek. Zugleich verweist das Unternehmen gerne darauf, was mit dem Mycoprotein des Koji-Pilzes alles möglich ist: „Wir können Fleischersatzprodukte nachbauen, die in Aussehen, Geschmack und Konsistenz nah an der Realität liegen“, sagt Fronzek. Schweineminutensteaks, Chicken Nuggets, Saltimbocca, Fischstäbchen, Thunfischsalat. „Es funktioniert einfach alles.“ Nur über eine Änderung des Flüssigkeitsgehaltes ändere sich die Struktur so, dass man all dies herstellen könne.

Fronzek ist nach rund zwei Jahrzehnten im Geschäft Profi genug, um zu wissen, dass der Weg vom gelungenen Start-up-Pilzexperiment mit einer Fünf-Liter-Glasflasche im Labor bis zu einer industriellen Produktion in großem Maßstab ziemlich steinig sein kann. Zumindest ein paar Steine hat er schon aus dem Weg geräumt. Zuletzt machte Hoffnung, dass der italienische Nudelgigant Barilla für sein „Good Food Makers“-Programm das deutsche Ernährungs-Start-up aus mehr als 100 Unternehmen als ein Gewinnerprojekt auswählte.

Produktion in der Brauerei

Eine ganz neue Kooperation gab Nosh nun am vergangenen Freitag bekannt. Man arbeitet mit der Brauerei Berliner Berg zusammen. In dem kleinen Unternehmen in Berlin-Neukölln steht eine Anlage für die Pilzfermentation. Zwei Tonnen Endprodukt sollen hier in einem Monat produzierbar sein. „Wir zeigen, dass Brauereien Lebensmittelzutaten in Koproduktion herstellen und gleichzeitig am selben Standort Bier brauen können“, sagt Nosh-Mitgründer Felipe Lino, ein Mikrobiologe, der vorher für den größten Brauer der Welt, AB Inbev, arbeitete. Betriebswirt Fronzek lobt den ökonomischen Charme. Nosh muss keine eigene teure Produktion aufbauen – und eine Branche, die unter rückläufiger Nachfrage leidet, erhält vielleicht neuen Schwung. Denn der Pilz wächst gut auf Maltoseextrakt, einem Abfallstoff von Brauereien.

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Das klingt alles fast zu schön, um wahr zu sein. Trotzdem lässt sich der Neugründer nicht von ambitionierten Geschäftsplanungen abhalten. Ende 2024 will er drei bis fünf Kunden bedienen und Umsätze in einer Eurogrößenordnung von „deutlich sieben-, vielleicht achtstellig“ erreichen. Letztlich könnte die Nosh-Technologie der Biomassen-Fermentation die Nahrungsmittelindustrie auf den Kopf stellen, glaubt Fronzek. Denn in drei bis vier Jahrzehnten erreichten die Produktionskapazitäten auf der Erde mit den heutigen Systemen ihr Limit. Sie seien nicht mehr in der Lage, alle Menschen auf der Welt adäquat mit Nährstoffen zu versorgen. Zwar ist nicht zu erwarten, dass ausgerechnet das kleine deutsche Start-up aus Berlin-Adlershof dann allein die Lösung dafür bereitstellt. Viele Unternehmen arbeiten gerade daran. Aber Tim Fronzek wäre schon zufrieden, w

FORBESBUSINESSFOOD & DRINK

Plant Based Fail: The Empty Promise Of Animal Meat Displacement

Michele Simon

Former Contributor

I focus on disinformation in the plant-based and food tech sectors.

5

Listen to article11 minutes

Meat Products Stocked In New York City

NEW YORK - DECEMBER 29: A butcher arranges meat products at a grocery December 29, 2003 in New York ... [+]

GETTY IMAGES

It has been a rough couple of weeks in the media for the plant-based meat category. The major black eye came from a BusinessWeek cover story by Deena Shanker with the painful title, “Fake Meat Was Supposed to Save the World. It Became Just Another Fad” and subtitle, “Beyond MeatBYND +5.4% and Impossible Foods wanted to upend the world’s $1 trillion meat industry. But plant-based meat is turning out to be a flop.”

Ouch.

The reaction from the vegan echo chamber was swift and childish.

Impossible Foods resorted to calling the article “another opinion piece” and oddly relied on Reddit users to defend the company, taking out a full-page ad in the New York TimesNYT +1.2%. Such an exorbitant and useless spend seems especially ill-timed given this week’s news of the company cutting 20 percent of its workers.

Meanwhile, social media exploded with various forms of outrage aimed at the Bloomberg reporter who wrote the piece, Deena Shanker. This common response is known as “shooting the messenger”, and at times crossed over into vicious attacks.

But lost in these knee-jerk reactions is the grim reality that the main promise of plant-based meat – that these products will displace animal meat – is unfulfilled and will likely remain so into the future.

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We can keep arguing over whether sales of plant-based meats are going up or down, or whether these products are healthy or not, of even if the meat lobby is paying Bloomberg to publish stories to bash the category. (This conspiracy theory was floated more than once on social media, including in a comment on Impossible Foods’ LinkedIn post.)

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At the end of the day, the only relevant question is this: Are meat eaters substituting plant-based meats for animal meats in any significant way?

Lying With Statistics

To date, we have no relevant data to indicate displacement is happening.

Too many people are blindly assuming that any sales of plant-based meats other than to vegans and vegetarians must mean that animal meats are being displaced. But this is not necessarily true. Even if we assume that a significant portion of purchasers are “flexitarian” – people who only sometimes eat meat – we still don’t know exactly what foods these consumers are displacing, or even if they’re displacing anything.

This story in Wired sums up the challenge well:

“Figuring out whether plant-based meats are replacing beef isn’t something you can tell from share prices or total retail sales. Instead, we have to rely on data from surveys and analyses of supermarket shopping carts. The evidence we do have suggests the Great Displacement isn’t happening (yet).”

So where are the claims of displacement coming from? Mostly, from the industry itself. In 2019, Impossible Foods claimed that over 95% of people who order their burger regularly consume animal products, and in that same article, Beyond Meat cited purchase data from a large retailer showing that more than 90% of consumers who purchased the Beyond Burger also purchased animal meat.

More recently, a 2022 analysis published in Nature purported to show that about 86% of purchasers of plant-based meat buyers also bought ground meat, and that about 2.79% purchased plant-based meats exclusively. Some have misrepresented this data on social media to “prove” that the category is not relegated to only vegans and vegetarians, and hence the critical media outlets have it all wrong.

However, all these sources rely on household panel data, which tells us what households are purchasing overall, not individual consumers. So it’s entirely possible and quite likely that one member of the household is eating plant-based meat while others are eating animal meat. Thus the stats can sound impressive, but tell us nothing about displacement.

Moreover, that same Nature study found that purchasing plant-based meats for the first time does not deter meat demand among those households. Study co-author Jayson Lusk confirmed all of this to me via email: “We're finding very little evidence of displacement,” he said.

Similarly, Dan Blaustein-Rejto, director of food and agriculture at the Breakthrough Institute, told Wired last year: “There’s relatively little evidence that plant-based meat alternatives are currently displacing conventional meat.” He also said the data suggests that most people are using plant-based meats as an extra source of protein rather than a direct replacement for meat.

In other words, it’s entirely possible that flexitarian purchases of plant-based meats are simply topping their (already vegetarian) pasta with some Impossible meatballs or Beyond sausages. We simply do not have the data to show us otherwise.

(I emailed both Impossible Foods and Beyond Meat to ask for a source for the claim that their products are displacing animal meat but did not hear back from either company.)

Selling More of Everything

Another response to the critiques has been, but just wait, it’s still early days! However, in the long term there is no viable economic path for displacement of animal meat because the goal of capitalism is always to sell more, not less.

There is zero economic incentive for the gatekeepers between food manufacturers and consumers— retailers and restaurants — to displace animal meat with plant-based meats. To the contrary, the goal is to simply sell more of anything and everything, especially in the highly competitive and low-margin world of food sales.

Retailers don’t want plant-based meats to displace animal meats. So while grocery chains may allow some very limited shelf space in the fresh meat department for the likes of Beyond Meat and Impossible Foods, animal meat is always going to be the main attraction simply because it’s a winning strategy.

Beyond Meat, (followed by Impossible Foods), made a Big Deal early on about having its products placed in the fresh meat department, not in frozen, and certainly not in what CEO Ethan Brown called the “penalty box”, meaning where other vegetarian and vegan products tend to be sold in a separate section, often in produce where only the most dedicated fans are likely to find it.

In early days, most new brands will pay retailers expensive slotting fees to obtain shelf space. But this practice is not sustainable over time, and brands must prove themselves through actual sales to remain on shelf.

(I asked both Beyond Meat and Impossible Foods if they pay slotting fees and got no reply. This article in BusinessNews postulates that the two brands are likely paying slotting fees.)

Retailers are a critical gatekeeper to how products are sold and merchandised and they are not about to do anything that interferes with profits from selling meat.

Similarly, fast food chains, which both Beyond Meat and Impossible Foods have been targeting, are not interested in displacing animal meat. Most restaurants are only including a vegetarian option to avoid the “veto vote”, which is what happens when one member of a group cannot eat at a given restaurant because they are vegetarian. QSR Magazine, which covers fast food, explains how to “overrule the veto vote”:

“As customers demand more complex menus, healthier options, and increased convenience, brands have to work harder to eliminate possible veto votes. It’s a common scenario nowadays to find groups of diners that vary in tastes; a vegan may dine with a meat-lover.”

That’s why restaurants tend to maintain at least one vegetarian option to ensure they get the entire group’s business. In this very typical scenario, not only is the plant-based option not being displaced, but an entire group of meat eaters is also now giving the restaurant its business, so more meat is being sold because of the plant-based option.

It’s high time for the entire sector to take a giant reality pill and stop making claims that are not substantiated by real world evidence.

Wild Claims and Predictions

The plant-based meat sector has put a massive target on its back by making outlandish predictions since the early days of when then-start-ups Impossible Foods and Beyond Meat took to using PR, instead of waiting for actual sales, to hype themselves to investors through the media.

For example, Pat Brown, founder (and former CEO) of Impossible Foods, many times repeated his fantasy that the meat industry will be “obsolete” by 2035. For example, he claimed in 2020 that “plant-based products are going to completely replace the animal-based products in the food world within the next 15 years. That’s our mission.”

That’s some magical thinking right there.

Beyond Meat’s Ethan Brown has also had his share of bold statements. For example, in 2019 (the year of the company’s record-setting IPO) Brown claimed that his products “would simultaneously help solve heart disease, diabetes, cancer, climate change, natural resource depletion and animal welfare.”

That’s quite a list of deliverables.

Such audacious and unsubstantiated claims are then amplified by animal rights groups and other vegan nonprofits such as the Good Food Institute, which celebrated Beyond Meat’s IPO with over-the-top rhetoric about phantom meat eaters switching over to plant-based meats, without any evidence to back up their dubious claims: “Breakthroughs in food science have seen these companies winning the affections of carnivores with delicious products that are indistinguishable from real meat.”

The data simply does not support any of these claims. And hoping for “better tasting products” and “more time” is continued magical thinking. The problems related to conventional meat production are not caused by lack of great tasting or even cheaper alternatives. The causes are inherently political, and only political solutions will make a difference.

Follow me on LinkedIn. Check out my website.

Michele Simon

Michele Simon

I am a public health attorney, food industry expert, and food policy advocate. I conceived of, organized, and founded the Plant Based Foods Association, the nation’s first and only membership association promoting the interests of plant-based food companies. For five years (2016-2020), I led the association to fight off the powerful meat and dairy lobbies and forged new marketplace opportunities for the plant-based foods industry. I have also written extensively on the politics of food and alcohol. My book Appetite for Profit, published 2006, was called “brilliant” by NYU Professor Marion Nestle. I have a master’s degree in public health from Yale University and a law degree from the University of California, Hastings College of the Law. My website: michelersimon.com

Fake meat was supposed to save the world. It became just another fad

Beyond Meat and Impossible Foods wanted to upend the world’s $1 trillion meat industry. But plant-based meat is turning out to be a flop

A frozen Beyond Burger plant-based patty. Photographer: AKIRA for Bloomberg Businessweek

Ever since founding Beyond Meat Inc. in 2009 with the then fantastical idea of making meat without animals, Ethan Brown has been giving the equivalent of one extremely long TED Talk.

In 2013 he took the stage at the Wired Business conference, explaining that the world had a very real greenhouse gas-emitting meat problem and that venture capitalists could make a bigger impact investing in fake meat than in solar energy. At Toronto's annual Ideacity gathering three years later, he said his goal was to replicate the "blueprint of meat." By the time he appeared at Goldman Sachs Group Inc.'s Builders & Innovators Summit 2019, he explained that his mission demanded the urgency and scale the US mustered for World War II and that his products would simultaneously help solve heart disease, diabetes, cancer, climate change, natural resource depletion and animal welfare. Just like technology had rendered the horse-drawn carriage obsolete, he told the crowd at the New York Times' climate conference this past fall, so, too, would his system of breaking down plants transform the protein at the center of the plate. "This," he said, "is something that I feel is inevitable."

Ethan BrownPhoto: Bloomberg

Ethan BrownPhoto: Bloomberg

Silicon Valley didn't need much convincing that a better veggie burger could become the next world-changing disruption. Whereas the quinoa-and-bean patties of yore were for the crunchy set, Brown's beef facsimile, concocted in a lab to look and taste like the real thing, meant the vast majority of meat eaters could give up their burgers without having to give up anything at all. Along with the venture capitalists came investors from every corner of culture—Leonardo DiCaprio, the Humane Society of the United States and former McDonald's Corp. Chief Executive Officer Don Thompson. Even Tyson Foods Inc., the biggest maker of real meat in the US, invested and then invested again, catapulting the young El Segundo, California-based startup to a $1.3 billion valuation by 2018.

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Bill Gates wanted in, too, backing not one but two companies with veggie burgers that "bleed" like real beef—Beyond, as well as its rival Impossible Foods Inc. Brown had licensed someone else's process, but Impossible was the brainchild of a Stanford University biochemist named Pat Brown (no relation to Ethan). When Pat founded Impossible in 2011, his big breakthrough was realizing that a molecule called heme was the key to meat's meatiness. He made heme with genetically modified yeast and patented the use of what the company called its magic ingredient: soy leghemoglobin.

Bill GatesPhoto: Bloomberg

Bill GatesPhoto: Bloomberg

Before Impossible had sold even a single burger, the company managed to raise $183 million. Pat also worked the circuit, including an actual TED Talk (technically, it was TEDMed) in 2015. Speaking in slightly more apocalyptic terms than Ethan, Pat referred to the "ongoing wildlife holocaust" caused by the world's insatiable demand for meat, while an assistant sizzled an Impossible Burger onstage beside him. "I know it sounds insane to replace a deeply entrenched, trillion-dollar-a-year global industry," he said, "but it has to be done." Four years later, when the New Yorker profiled Impossible, Pat predicted his company would "take a double-digit portion of the beef market" by 2024 before sending it into a "death spiral." Next he would target "the pork industry and the chicken industry and say, 'You're next!' and they'll go bankrupt even faster."

But Big Meat is still alive and well. After Beyond went public in 2019—at the time the most successful major initial public offering since the 2008 financial crisis—competitors rushed into the space, followed by a categorywide pandemic surge. Since then the industry has plunged. Supermarket sales of refrigerated plant-based meat plummeted 14% by volume for the 52 weeks ended Dec. 4, according to retail data company IRI. Orders of plant-based burgers at restaurants and other food-service outlets for the 12 months ended in November were down 9% from three years earlier, according to market researcher NPD Group.

Beyond lost sales in almost every channel last quarter. Over the past year it laid off more than 20% of its workforce, lost more than half of its C-suite and halted projects including vegan hot dogs and the next alt-protein frontier of cell-cultured meat, according to people with knowledge of the matter, who asked not to be named discussing private information about the company. None of the biggest fast-food chains that had announced partnerships with Beyond—KFC, Pizza Hut and, most important, McDonald's—have put a single permanent item on their US menus. While an index of packaged-food companies on the S&P 500 was up about 4% from a year ago, as of Jan. 17, Beyond's stock price is now hovering around $16, down about 76% from a year earlier and roughly 93% from its peak in the summer of 2019.

Impossible, meanwhile, is faring better—but Pat is out at the company. Last April he stepped down to chief visionary officer, replaced as CEO by a Chobani Inc. executive, before taking a leave of absence. Under new CEO Peter McGuinness, Impossible has spun up new products such as animal-shaped faux chicken nuggets and blitzed supermarkets, leading to more than 50% retail sales growth in the US in 2022. While it has added restaurant partners, some of its long-standing ones are finding consumer excitement has either hit a wall or is declining. Shares of Impossible, a private company, are currently trading at around $12, says Prab Rattan, head of capital markets at Hiive, a marketplace for private stock trading. That's about half the price during its last fundraising round, based on PitchBook data.

Plant-based meat's most reliable enthusiasts at this point are those original veggie burger stans, vegans and vegetarians. The all-important meat eaters do partake, but at a much lower frequency. "They're just not that into it," says Chris DuBois, head of IRI's protein practice.

How did an industry with so much riding on it—backed by so much money—suddenly fizzle out? The companies declined to make Ethan Brown and Pat Brown available to talk to Bloomberg Businessweek, but at that New York Times climate conference in October, Ethan pointed his finger at the actual meat industry for fake meat's headwinds. "They are doing their very best today to suggest that our process is somehow unhealthy or that our products are full of chemicals," he said. "These things are not true."

Whatever critiques the meat industry is lobbing are the same ones plenty of consumers are figuring out for themselves. Like fat-free Snackwell's cookies or Lay's olestra-laden WOW Chips—or any other glut-without-the-guilt food trend that periodically cycles in and out of the zeitgeist—the incremental benefits are eventually offset by concerns over what else might be in there. Many meat eaters initially excited by fake meat, who didn't mind the not-quite-there taste or texture, eventually took a closer look at the ingredient list and couldn't figure out whether they were actually trading up. Were they eating these burgers to curb carbon emissions or lower their blood pressure? Was it a healthier alternative or a sodium-filled, overprocessed substitute? Plant meat still costs more than the real thing, and with inflation pushing up prices across the supermarket, many grocery shoppers have swapped the expensive imitation for chicken or, in some cases, beans and lentils.

Meatless meat, it turns out, seems less a world-changing innovation than another food trend whose novelty is wearing thin. "Before we were seeing this incredible growth rate. But when you lose that momentum, you lose your certainty around how big plant-based meats can be," says Thomas George, portfolio manager at investment research company Grizzle, who in 2019 predicted plant-based meat could overtake 10% of the meat industry in 10 years if it could match meat's prices. "The opportunity for this category," he says now, "is more murky."

Before Beyond Meat unveiled the Beyond Burger, there was the Beast. When Ethan introduced the frozen patty in 2015, the company called it a "protein shake on a bun." Although he ended up ditching it, the Beast's health claims, such as high levels of protein and zero gluten or soy, remained front and center on Beyond Burger's packaging. (Whenever asked, Pat defended the health cred of Impossible's product against beef, though he preferred to talk about replacing animal agriculture by 2035.) But nothing preached the virtues of plant-based eating to the masses like The Game Changers, a James Cameron-produced documentary that hit Netflix in 2019.

The Game Changers followed world-class vegan athletes, with cameos by doctors, scientists and even Arnold Schwarzenegger, who, before he became mostly vegan, once told Sylvester Stallone that he "hit like a vegetarian." Veganism, according to the film, would make a person not only healthier but also stronger, with better endurance and even longer, harder erections.

Ethan added the film to his arsenal. "If you look at movies like Game Changers, etc.," he told Bloomberg Television in 2019, "you can affect even individual day performance, from a student-athlete, for example, through the consumption of our products over animal protein." He said Beyond's own athlete ambassadors, including NBA stars Kyrie Irving and Chris Paul—also investors in the startup—were "adopting our products in their training regimes, and they're seeing great results."

Chris PaulPhotographer: Christian Petersen/Getty Images

Chris PaulPhotographer: Christian Petersen/Getty Images

The Beyond Burger originally was sold in supermarkets, while Impossible went with celebrity chefs such as David Chang. By the end of 2019, Carl's Jr., Dunkin' and White Castle were all selling some Beyond or Impossible product or other—and Burger King had launched the Impossible Whopper nationwide. The food giants didn't want to get left behind either. Tyson had shown an interest in buying Beyond, according to former Beyond board member Greg Bohlen. When that didn't pan out, the meat company announced plans for its own plant-based "billion-dollar brand." (Tyson declined to comment.) Nestlé SA introduced an Awesome Burger, and Conagra Brands Inc.'s CEO said it would create "the next generation of beefless burger."

At first, fake burgers and sausages seemed like a potential solution to Americans' obsession with red and processed meats, which have been linked to cancer and other chronic diseases. But over the years, skepticism about their healthfulness grew. Within months of Beyond's IPO, onetime fan and whole-foods maven Mark Bittman criticized the fake meat products for their "hyperprocessing." Chipotle Mexican Grill Inc.'s CEO said they didn't fit with the fast-casual chain's "food with integrity" mantra. Even John Mackey, co-founder of Whole Foods Market Inc.—the grocer that had been instrumental in introducing the category—went on the record calling plant-based meat "super, highly processed foods." (The Center for Consumer Freedom, a front group that represents tobacco, alcohol and meat companies, ran a Super Bowl ad in February 2020 attacking fake meat's ingredients with a mock spelling bee that repeated long-held health advice: "If you can't spell it or pronounce it, maybe you shouldn't be eating it.")

Still, that criticism hadn't yet made its way to people such as Michelle Darby, a mother stuck at home with four kids, in Marlton, New Jersey, during the early days of the pandemic. She found The Game Changers on Netflix. "It gave a very compelling argument," she says. "And I'm on the borderline of high cholesterol."

Darby, like many others in lockdown, started buying faux meats. The real thing was scarce, and people had extra cash to try out this buzzy new product. Americans bought 5.3 million units of fresh-meat alternatives in the eight weeks ended April 25, 2020—three times the amount from a year earlier, according to Nielsen Holdings Ltd. Suddenly, Beyond's prediction in one of its investor pitch decks that fake meat was on track to become the new fake milk was looking increasingly plausible: Just as the alt-milk companies could claim to be 13% the size of the $16.1 billion dairy milk category with new products such as oat milk, alt-meat would similarly undercut the even bigger $270 billion US meat industry. ("That's the floor," Ethan said at a 2019 Barclays Plc conference.)

As Darby stocked up, she noticed that she and her family were gobbling up the chickenless nuggets at a much faster pace and that the imitation hot dogs left her feeling uncomfortable. At a checkup with her doctor she mentioned the diet changes they'd made—the fake chicken nuggets, the Impossible sausage sandwich at Starbucks—and their disappointment with the lack of results. The doctor had a simple explanation: "You are eating processed foods."

Darby went home and looked at the packaging, taking particular notice of the salt content. "It should have been obvious to me the whole time," she says. She stopped buying plant-based meats, except for an occasional purchase of Impossible ground beef. Meanwhile, she's doing what a lot of consumers are: going back to meat. "If they [her family] want hamburgers, we'll occasionally buy ground meat or we'll make ground chicken, and they don't notice the difference," she says.

In 2020 half of Americans thought faux meats were healthy; now 38% think so, a recent report from Citi Global Insights shows. Dr. David Katz, founding director of Yale University's Prevention Research Center, who appears in The Game Changers, says the Beyond Burger and its ilk are "ultraprocessed"—made from processed ingredients such as pea protein, potato starch and potassium chloride. When comparing them with fast-food burgers, he cites the environmental and animal welfare advantages but says that any health benefits are still unclear. "At worst," he says, "it's a lateral move." A Beyond Meat spokesperson told Bloomberg Businessweek that there are "well-accepted health benefits of plant-based meat" and directed Businessweek to two health professionals: Stanford's Christopher Gardner, who's received funding from Beyond Meat, conducted a small study that pointed to improvements in weight and cholesterol. He says the health benefits he identified, however, have yet to be replicated. "You can't answer a question with only one study," Gardner says. And Dr. Michael Greger, author of How Not to Die, says that fake meat is a better choice than a fast-food burger, but that doesn't make it good for you. "Nobody should be under the illusion that these are health foods," he says.

Nowhere is this more obvious than when you discover that a key ingredient in Beyond Meat has its origins in Dippin' Dots, the tiny "beads" of ice cream frozen with liquid nitrogen, available in flavors including banana split and cotton candy. Beyond started working with Dippin' Dots LLC in 2019. The Dots business was sold in June 2022, but Beyond still works with Scott Fischer, its former CEO, through his company, Cryogenic Processors LLC. Beyond buys fats such as expeller-pressed canola oil and refined coconut oil, which Fischer processes into "little pellets or cryogenically frozen balls of fats," he says. Cryogenic Processors sends the fatty balls back to Beyond to mix with water, rice protein, cocoa butter, methylcellulose and more than a dozen other ingredients found in the Beyond Burger.

The white globules are meant to give the burgers a meaty juiciness, but plant-based fats can also emit an off-putting smell when some of these products are cooked, says Tom Mastrobuoni, who led the second Tyson investment in Beyond and is now chief investment officer at the food-tech-focused Big Idea Ventures LLC. Commenters online have compared the odor of Beyond's raw plant meat to that of cat food, and one message board poster said he had to ventilate his kitchen to clear the air after cooking it. "If any other food smelled that way, I would throw it out," says Jeremy Sklarsky, a former Beyond customer who tried the products out of health and environmental concerns before going back to beef.

In September, Beyond Meat Chief Operating Officer  Doug Ramsey was arrested in Arkansas for allegedly biting someone's nose in an altercation after a college football game. Ramsey, a former Tyson executive, was one of the meat industry vets Ethan had wooed in 2021 to help Beyond expand. By mid-October, Ramsey, along with the company's chief financial officer, chief growth officer and chief supply chain officer, was gone.

The love affair between Beyond and the fast-food giants has faded, too. Dunkin'—once the company's biggest-name partner—pulled the faux sausages in its breakfast sandwiches from almost all the menus nationally in 2021. Beyond's delayed chicken tenders rollout had no big-name chains in sight. Taco Bell tested Beyond's carne asada, but last month its CEO told Axios the reviews were "mixed" and a national rollout isn't likely coming anytime soon. Meanwhile, photos and documents from Beyond's plant in Pennsylvania—where both the KFC nuggets and Pizza Hut pepperoni were partially manufactured—revealed that listeria and foreign materials such as wood and string had been showing up in products made there as late as May 2022. (A spokesperson for Beyond Meat said at the time that the company's food-safety protocols "go above and beyond industry and regulatory standards.") Yum! Brands Inc., which owns Taco Bell, KFC and Pizza Hut, didn't respond to requests for comment.

Beyond also trialed its burger at about 600 US locations with McDonald's, its most important customer, with little to show for it. For a brief moment in April it looked like the McPlant meatless burger would stay for good. Fast Company misreported that the McPlant would become a permanent menu item, sending Beyond's stock price up as much as 34%—until McDonald's disputed the news, causing shares to fall just as quickly. In July a JPMorgan Chase & Co. analyst said he'd checked with 25 Mickey D's: None were offering the McPlant anymore. "Not surprisingly, the reason sometimes being cited is that the product did not sell well enough," he said. Then came the nose-biting fiasco. "Negative PR around a senior member of management with key MCD relationships likely hurts whatever slim chances may have remained," Piper Sandler Cos.' Michael Lavery wrote in a note. McDonald's still sells the McPlant internationally, but it hasn't confirmed results of the US test or future plans.

When Beyond hired the world's biggest influencer, Kim Kardashian, it managed to flub that, too. In the spring of 2022 the company announced its splashy new "chief taste consultant." But it quickly led to viral mockery when online sleuths noticed she didn't seem to actually be eating the Beyond Burger in a commercial. (Kardashian later released footage from the set showing she had, in fact, swallowed the food.)

Impossible, meanwhile, is discovering that upending animal agriculture is difficult. Burger King has added another Impossible Burger to its mix, but after trying the company's faux chicken nuggets, a chicken sandwich and sausage patties, it didn't put any in its regular lineup. FAT Brands Inc. restaurants are selling a steady million Impossible Burgers a year—which is good, but not as good as beef, whose sales are climbing. At Bareburger, also an Impossible early adopter, the burger's sales went from "astronomical" to about 6% of all burgers and sandwiches in 2021 to 4% in 2022, says Euripides Pelekanos, the chain's CEO. "The fanfare has definitely subsided," he says. The price of the burger—more than that of the beef, elk and black bean versions—doesn't help.

Pat Brown's replacement at Impossible, McGuinness, an ad industry veteran who left yogurt maker Chobani last year, says he has new growth plans for the Redwood City, California-based startup. "I don't want to talk about the category declining—it doesn't exist," he says, even though Impossible has been trying to lead it for the better part of the past decade.

This time, though, McGuinness's plan is to "operate like a food company." Instead of predicting the end of the meat industry, the new CEO talks about reaching carnivores by boosting total distribution points, doubling consumer awareness and bundling promotions for his faux chicken nuggets with faux pork products, so shoppers who like one will try the other. Just like a yogurt shelf grabs customer attention with variety, so, too, will Impossible products. In October he laid off 6% of the staff as part of a broader restructuring, telling employees the company was focused on its "R&D and innovation pipeline." Pricing, which has already come down, could match beef as early as the end of the year, he says, as his costs continue to improve with increased efficiency. Then there's the burger's nutritional profile. "The cake for us is to make a delicious product," McGuinness says. "The icing—it's better for you, better for the planet."

Kim Kardashian, taste consultant.Source: Beyond Meat

Kim Kardashian, taste consultant.Source: Beyond Meat

Three and a half years ago, New York's Javits Center hosted the first Plant Based World Expo. Amid hawkers of seitan corned beef, pea-and-tomato-based chorizo and mold-based dog treats, the real excitement was Beyond. Fresh off its IPO, the company's executive chair was a keynote speaker. "I wish I had invested in them," Andy Levitt, founder of vegan meal-kit startup Purple Carrot, said at the time. When Levitt started his company in 2014, vegans were the "tattooed girl with Birkenstocks in Vermont," he said. Beyond's products had catapulted an entire generation of startups, becoming the "gateway drug to plant-based foods."

The 2022 Expo felt a lot more like a regular old trade show. There were no signs of Beyond, unless it was from an exhibitor answering a question to differentiate itself from the onetime star. Booth after booth showcased products such as Shark Tank-backed faux deli slices and textured soy protein "jerky," but few were good enough to go back for seconds, many more so unpalatable that this meat-eschewing Bloomberg reporter spit them out. By far the best-tasting food at the event was in the Italian Pavilion, where chefs served cheeseless vegetable pizzas and pasta puttanesca sans the anchovies—no imitation animal protein to be found. Asked what he was doing at the fake meat show, Italian chef and restaurateur Fabrizio Facchini was taken aback. "We also have a lot of plant-based," he said, relying on the literal meaning of the phrase more than on the marketing term. "We don't use cheese on everything."

When industry watchers were still figuring out whether plant-based meat might pull an alt-milk-size disruption, many missed two key differences: lactose-intolerant consumers and milk's primary use as an ingredient, not a main course. Many soy, almond and oat milk drinkers add it to their coffee because real milk simply isn't an option. But they're mostly not drinking it by the glass. Even predictions of a sales rebound for plant-based meat are dwarfed by what's happening in dairy. Bloomberg Intelligence's Jennifer Bartashus wrote in November that in the second half of 2023, "we expect plant-based dairy sales to rise 6-8% and meat alternatives 1-2%."

Beyond Meat's current market capitalization is about $1 billion—down from its peak of more than $14 billion. Bringing costs down is the company's priority as it pledges to finally become cash-flow positive in the second half of this year and tries to keep up its dwindling cash reserves. In the company's November earnings call, Ethan Brown talked up another limited-time offer with Panda Express Inc. and the company's 2022 food award from People magazine. The analysts, though, peppered him with questions about high inventory levels and why Beyond was making only ingredients instead of prepared meals. Brown blamed inflation and shifting consumer tastes as blips in his long-term mission. "I am certain that as we hit price parity with that, as the products become indistinguishable, as the climate situation worsens, as people get a clear sense of what the real health benefits are," he said, "this conversion will happen."

The big food companies have cooled on the category, too. Tyson scrapped its plant-ish burger—a half-beef, half-pea-protein concoction that was supposed to launch its future "billion-dollar brand." Products from Kellogg's Morningstar Farms, Conagra Brands' Gardein and Nestlé's Sweet Earth are all still selling, some well, but none are breakout hits.

What remains looks more like a niche category than a meaningful displacement of an entrenched industry. After Beyond, Impossible and their copycats spent years trying to seduce everyone away from meat, it appears their best customers are, well, the 5% of the population who didn't eat meat in the first place. Kevin Lindgren, director of merchandising at food distributor Baldor Specialty Foods Inc. in New York, says more restaurants are ordering plant-based burgers simply to make sure they have something to serve vegetarians "that's not a salad or cauliflower." Alt-burgers' continued expansion into restaurants is largely being propped up by establishments protecting themselves against this "veto vote"—the lone nonmeat eater in a group of diners who can thwart a destination decision if there's not a suitable meatless entrée. "It's frozen, throw it in the freezer," Lindgren says, summarizing restaurants' enthusiasm. But even that's not a sure shot. Plenty of vegetarians would prefer a veggie burger made of actual vegetables, and definitely not one that "bleeds."

Leonardo DiCaprioPhotographer: John Angelillo/Alamy

Leonardo DiCaprioPhotographer: John Angelillo/Alamy

Impossible is now venturing beyond the coasts, where many have already moved on from fake meat, hoping to jump-start interest in the rest of the country. (Lindgren says he recently spotted an Impossible Burger on a menu in a South Dakota sports bar.) But when Impossible sausage was added to the menus of more than 600 Cracker Barrels last summer, the company quickly got a taste of this new customer base. "YOU CAN TAKE MY PORK SAUSAGE WHEN YOU PRY IT FROM MY COLD, DEAD HANDS," one of the thousands of angry commenters wrote when the Southern country-themed chain posted the new offering on Facebook.

Meanwhile, a new meat alternative has found its way into the next hype cycle: cellular meat. Grown in giant tanks from cells harvested from living animals, lab-grown beef, chicken and fish are theoretically better for the environment than the real thing and should taste as good. Startups in this space have raked in $2.6 billion in funding from investors including, once again, Bill Gates and Leonardo DiCaprio. The category will have to overcome even bigger hurdles than plant-based meat, from the massive amount of energy required to make the products to exorbitant costs. But for boosters, its potential is already limitless. "This," Whole Foods co-founder Mackey said after investing in cellular startup Upside Foods Inc., "could change the world."

Disclaimer: This article first appeared on Bloomberg, and is published by special syndication arrangement.

Fermenting the Future of our Food System with Nosh.bio

Maresa Buttlar

Earlybird's view

Maresa Buttlar

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Earlybird's view

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Apr 21

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Nosh.bio Co-founders Tim Fronzek (left) and Felipe Lino (right)

By Partner Dr. Christian Nagel & Maresa von Buttlar, Earlybird Digital West

Plant-based products were initially lauded as the key to a more sustainable food system, with promises of reducing greenhouse gas emissions, land use, and water consumption.

However, in recent days, these products have received some rough press (e.g., see Bloomberg or Forbes), as they often fail to meet consumers’ expectations in terms of taste, price, functionality, and nutritional qualities — compared to their animal-based counterparts. These factors have been a major barrier to their adoption. So while plant-based products continue to hold promise for a more sustainable food system, their success will depend on improving these key factors and addressing consumer concerns.

And this where Nosh.bio comes into play:

Nosh.bio develops a new class of fermentation-based ingredients that provide functionality, eliminate the need for chemical additives, and improve the nutritional value of plant-based products.

In fact, Nosh.bio uses biomass fermentation and a proprietary downstream process to create a versatile ingredient platform. Their platform leverages a highly diverse biomass that offers a range of culinary possibilities: While some applications may call for a somewhat ‘tasteless’ version of the biomass, such as ice cream or pancakes, others may benefit from its rich umami flavor, particularly in meat-based applications like chicken or pork.

This diversity means that Nosh.bio’s platform can create versatile ingredients for a wide range of food products, or even as a standalone product.

Since the biomass can possess gelling, binding, texturizing, emulsifying and foaming functionalities, it eliminates the need for chemical additives such as methylcellulose; it also combines various capabilities for which one currently need separate ingredients. Additionally, it provides a superior nutritional profile to products — due to its high protein content. Their platform thus provides clear benefits for all involved parties: consumers, food manufacturers and the environment.

Our hypothesis is that the winning player in the space will have to move fast to drive down costs and provide great products at competitive prices.

We believe that Nosh.bio can do exactly that. With a B2B approach, the company can leverage the distribution channels and established brands of existing players, reducing the need for significant investment in building its own brand. Furthermore, Nosh.bio utilizes a fungal strain that minimizes regulatory hurdles, enabling rapid entry into the market. This strain also offers several different scaling options, which helps the company overcome traditional barriers in the space.

Last but definitely not least, the company’s team comprises seasoned professionals with deep scientific knowledge and a track record of strong execution, making them well-equipped to successfully implement their innovative approach.

Fermenting the future

At Earlybird, we are excited to announce that we are leading Nosh.bio’s 3.2 mn EUR seed round alongside Clear Current Capital, Grey Silo Ventures and Good Seed Ventures. Tim, Felipe, and the full Nosh team, welcome to the #EBVCgang. We cannot wait to support you on your journey to revolutionize our food system!

Are you building something exciting in the FoodTech or AgTech space? Then make sure to reach out to maresa@earlybird.com!

HOW TO GROW KOJI

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This guide for growing koji is designed to make the process as simple as possible.

This is a fool-proof guide for growing koji at home. In addition to providing an easy-to-follow koji growing recipe, I’ll also share the reasons why this particular process is so effective.

The Noma Guide to Fermentation is the best koji guide on the market (and it’s how I learned to grow koji), so if you want to dive deep into the koji-growing hobby, the Noma Guide is essential.

But the Noma Guide can be a bit overwhelming, and some of the lessons I’ve learned about effective koji production aren’t covered in the book. So consider this guide the Koji Recipe for Dummies. Let’s go.

KOJI 101

Koji is a mold also known as aspergillus oryzae. It’s a magical ingredient that can transform your cooking. Koji grows when koji spores (which are a powder that can be purchased online) are applied to cooked starchy substrates such as barley or rice. Once grown, koji is an essential ingredient in soy sauce, miso, sake, and many other umami-rich foods.

Koji takes about two days to grow. But it only grows under certain conditions. To grow koji, you need:

- The right substrate: The barley or rice must be polished (or “pearled”), which means the substrate’s protective layers (the husk and bran) have been removed. This is because koji cannot penetrate these layers. Thankfully, just about all rice you buy is polished, and it’s easy to buy pearled barley.

- The right cooking method: The substrate must be cooked so that it is soft but not soggy. And it can’t be too wet. To achieve this, the barley or rice is typically steamed.

- The right temperature: Koji grows best at around 86ºF, and it dies at around 108ºF. To ensure the koji is kept at the right temperature, the koji is typically placed in a temperature-controlled environment with plenty of airflow.

- The right humidity: Koji grows best at around 70% humidity. To achieve this, the koji is typically placed in a humidity-controlled environment.

To control temperature and humidity, most people make a fermentation chamber. Building a fermentation chamber for growing koji is easier than you’d think. With the right equipment, it only takes 10 minutes.

How to build a fermentation chamber

My fermentation chamber

My fermentation chamber

THE KOJI GROWING PROCESS

At a high level, koji recipes are only a few steps long. I’ll describe the high-level steps then get into the details. Moving forward, I’ll refer to the substrate used as only barley, because that is my favorite substrate to use.

1. Cooking the barley: The barley is soaked for a couple hours then steamed until it is soft but not soggy.

2. Inoculating the barley: The barley is placed in a kitchen towel-lined hotel pan and then dusted with koji spores.

3. Growing the koji: The barley-filled hotel pan is placed in the fermentation chamber for two days for the koji to grow. The koji is periodically monitored and adjusted to ensure it doesn’t overheat.

To do it well, you’ll need to know a bit more about the process. We’ll get there.

WHAT YOU’LL NEED

1. A fermentation chamber. See my full guide here.

2. Koji spores. I highly recommend the white koji spores from fermentationculture.eu. Their a small company of koji-obsessed entrepreneurs selling the best quality spores I’ve been able to find. They are based in Europe but ship almost everywhere.

3. Thermometer. You need to use this before adding the koji spores to the barley. Otherwise, you risk adding the spores when the barley is too hot (which kills the spores). I have this one.

4. Pearl barley. You’ll use about 500 grams per batch of koji, so I buy this pack of 4.

5. Kitchen towels: You need 2 kitchen towels, preferably 2 you don’t use for anything else. I use these. Be sure to wash them before using them for the first time.

6. Kitchen scale: If you use too much barley in one batch, you risk the koji overheating. I weigh 500g of barley for each batch of koji with a kitchen scale. I also use the scale to create my koji/flour mixture.

STEP 1: COOKING THE BARLEY

In this step, we aim to cook the barley until it is soft but not soggy.

You’re probably used to cooking barley (or rice) by simmering it in water. This will not work. It will make the barley too soggy (even if it doesn’t look soggy) and the koji won’t grow.

Instead, you’re going to have to soak and then steam the barley. Don’t worry, you don’t need a steamer to steam. Here’s what you do:

1. Put 500g of barley in a bowl and fill the bowl with water. Use more water than is necessary to merely cover the barley, because the barley will soak up some of the water.

2. Leave the barley in the water for 2 hours at room temperature. For food safety reasons, if you plan on soaking for more than 2 hours, do it in the fridge instead. I’ve soaked in the fridge for up to 8 hours before.

3. Rinse the barley in the sink with clean water multiple times until the water is no longer cloudy.

4. Put the barley in your steamer and begin steamer. If you don’t have a steamer:

- Boil water in a dutch oven or a pot with a lid.

- Put the barley in a strainer on top of the pot, ensuring the water does not reach the strainer.

- Put the dutch oven/pot lid on top of the pot.

- Continue to boil (ensuring the water never fully evaporates).

5. After 20 minutes of steaming, use a spoon to mix the barley. At this point, you can also take a single piece of barley to see how done it is (see next step for how).

6. Continue cooking the barley until it is done, checking and mixing every 5-10 minutes. I’m not going to give you a time estimate for this, because it is very variable! Instead, you can check if the barley is done by biting it. If there is a white inner center, the barley isn’t done. If the center is a uniform brown, you are good to go.

Not done (white center)

Not done (white center)

Done (uniform center but not soggy)

Done (uniform center but not soggy)

Close up of cooked barley. It doesn’t look soggy at all, and each piece is totally distinct

Close up of cooked barley. It doesn’t look soggy at all, and each piece is totally distinct

Placing the cooked barley in its hotel pan

Placing the cooked barley in its hotel pan

7. As soon as you’ve confirmed the barley is cooked, remove it from the heat (as further cooking will make it soggy).

8. Immediately pour the barley into a kitchen towel-lined hotel pan. Mix it around with a spoon a few times to keep the excess steam from overcooking the barley.

STEP 2: INOCULATING THE BARLEY

In this step, we aim to dust the koji spores on the barley so that they will produce koji.

Since the koji spores are very concentrated, this step is easiest (and least wasteful) when you combine the koji spores with flour. I recommend combining all your koji spores with flour as soon as you receive them so that you only have to do this once.

1. Weigh the spores.

2. Put 5x the weight of the spores in flour into a microwave-safe bowl. Microwave the flour for one minute. This pasteurizes the flour (by killing salmonella), which will allow you to use the koji in raw preparations in the future.

3. Once the flour cools down to 86ºF or lower, combine it with the spores. Store in a cool place in an airtight container.

Once you have your koji/flour mix, here are the steps to inoculate the barley:

1. Wait until your barley has lowered in temperature to 86ºF. Koji dies at 108ºF, so you risk ruining your batch if you add your koji spores too early.

2. Dust the barley with your koji/flour mix. I do so as follows:

- With your hand one foot above the barley, dust 1/2 teaspoon of koji/flour.

- Mix the barley around with a spoon. Ensure that you mix from the corners too.

- Dust a second 1/2 teaspoon of koji/flour.

- Mix the barley around with a spoon a second time, and then spread the koji out into an even thin layer.

STEP 3: GROWING THE KOJI

In this step, we aim to keep the koji at the perfect temperature and humidity for growth. The fermentation chamber helps, but you’ll need to do a bit of work, too.

Here are the steps for hours 0-24:

1. Place the hotel pan of koji/flour-dusted barley into the fermentation chamber.

2. Put the thermostat’s probe into the barley (i.e. buried halfway into the barley).

3. Cover the barley with a barely damp kitchen towel. This serves to prevent over-drying at the top level. The towel should be just the tiniest bit damp and certainly not dripping wet.

4. Place the humidistat’s probe on top of the kitchen towel.

5. Turn on the thermostat (set to 86ºF with 2ºF plus/minus) and humidistat (set to 72.5% with 5% plus/minus).

6. Close the lid of the cooler. I don’t close it all the way so that there is enough airflow. The way i do this is by stacking the probe wires from the thermostat and humidistat on top of one another, which keeps the lid raised by just a centimeter.

7. Leave the koji just like this for the next 24 hours.

I often find that the humidity rises well above 80% during this first day. To regulate the humidity, I occasionally open the lid of the cooler further or even wipe the insides of the cooler with a paper towel.

After 24 hours have passed, you’ll start to see some koji growth. Just tiny specs. You’re making progress.

1. At hour 24, mix the barley around so that it is evenly distributed. Mixing it (and spreading it out in an even thin layer) also helps to prevent overheating. I mix it while wearing rubber gloves.

2. If the kitchen towel has fully dried, lightly rewet the kitchen towel and place it on top of the koji again.

3. Periodically from hour 24 to around 48, monitor the koji to ensure that the temperature does not creep too high beyond 86ºF. Maintaining temperature becomes increasingly difficult as the hours go on, because the koji begins producing its own heat! It produces so much heat that it can actually reach 108ºF, thus killing itself. Some temperature increases are inevitable (and my koji batches usually end with a temperature around 103ºF), but the better you are able to control the temperature the more evenly the koji will grow.

4. When your koji temperature rises too high, there are steps you can take to address it:

- Break up and mix the koji again (like you did at hour 24). If you do this too often, the final result won’t be a single block of koji. But that’s fine! Optimize for good koji over pretty block of koji.

- Temporarily remove the hotel pan and place it on a cool countertop. Even 5 minutes like this can lower the temperature significantly.

- Add a fan! I don’t have a small fan, but if you do, you can add it to your cooler (below the hotel pan) to provide additional air from below to cool the koji.

5. Your koji will probably be done at around hour 48, but this is just an estimate. The best way to know when it is done is to simply look at it and smell it:

- If a blanket of white fully covers the koji, it is done. You did a great job!

- If the koji starts to show green or yellow spores, it is done. That means it is sporulating and you probably struggled with temperature control. Heavily sporulated koji doesn’t taste as good, so you should end the process as soon as you see sporulation.

- If the koji smells like ammonia, the wrong bacteria took hold. You should throw the batch away.

Koji gone wrong: sporulation. This koji probably grew too fast from poor temperature control or was left to grow for too long.

Koji gone wrong: sporulation. This koji probably grew too fast from poor temperature control or was left to grow for too long.

Koji gone wrong: sporulation and too dry. This rice was either not cooked enough or the humidity was too low.

Koji gone wrong: sporulation and too dry. This rice was either not cooked enough or the humidity was too low.

Here is my finished koji batch. When all goes well, it is a single block of white goodness.

My finished koji batch. When all goes well, it is a single block of white goodness.

FINISHING AND STORING YOUR KOJI

Once you take your finished koji out of the fermentation chamber, put it in the fridge in an airtight container. The flavors improve with a few hours in the fridge, so I recommend doing this regardless of what you plan to do with it next.

You can keep the koji in the fridge for up to a week before you use it in something else. Otherwise, you can:

- Freeze it: It will last multiple months frozen.

- Dehydrate it: I dehydrate it at 140ºF for a few hours.

TROUBLESHOOTING

Having issues? Comment below and I will address them in this section.

Koji grown on barley

Koji grown on barley

Soaking barley before steaming

Soaking barley before steaming

Steaming the barley with a dutch oven and a strainer

Steaming the barley with a dutch oven and a strainer

Distributing the koji/flour mix

Distributing the koji/flour mix

Putting the barley into the chamber

Putting the barley into the chamber

One day of growth (after mixing). It’s okay if you see less white than what you see here.

One day of growth (after mixing). It’s okay if you see less white than what you see here.

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How to Grow Koji 麹

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The word koji (Kouji/麹) in Japanese is a general term of a grain that has been inoculated with a species of fungus known as Aspergillus oryzae. In a way, the complex and savoury flavours that koji provides is what makes the food at Noma different as it no longer needed to make animal stocks the conventional way, achieving the umami notes in their dishes using various fermented products, namely koji. At Noma, we sometimes made up to 100 kg of barley koji a week and maybe a tenth of that in rice koji as a gluten free alternative. The information here is what I remembered it as when I was working there combined with what I learned living in Japan. I was working at Noma around the time that they published the book- The Noma Guide to Fermentation. Having had worked there, I can say for certain that the methods and recipes used in that book are exactly what we used in the restaurant and therefore if you’re looking for more information I highly recommend you buy that book.

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Koji in Japan was actually not originally cultivated on rice but on alternate grains as rice was typically sent to lords and the aristocrats as a form of tax. This meant that farmers had to make do with whatever other grains were available. As the production of rice in Japan steadily increased to become a common everyday staple, koji cultivation on rice started to overtake that of other grains, with non-rice cultivated koji being very hard to find in Japan today. Today, koji is used in the production of many everyday Japanese kitchen ingredients including soy sauce, miso and sake.

In the same way that most fungi grow, the spores of a fungus grow root like structures into the substrate they land on called hyphae. These hyphae grow further and further into the substrate, forming a complex network known as a mycelium. Like plant roots, nutrients are absorbed through these hyphae. Unlike soil however, the substrate on which the hyphae grow in do not have readily available nutrients in an absorbable form. Koji gets around this problem by secreting enzymes from their hyphae before absorbing the digested nutrients back through the hyphae. Think of it as digesting your food first before eating it. The enzymes secreted by the koji include amylases (for digesting starch), proteases (for digesting proteins) and lipases (for digesting fats), which breakdown the nutrients into their constituent building blocks.

Grains used to grow koji on are almost always polished to some degree as the koji hyphae would not be able to penetrate the husk of the grain. It is still possible to grow koji on non-polished substances of course, but it can be a lot trickier to do. Koji is sometimes grown on brown rice as well, which itself still has the bran and germ attached but the husk/hull removed. The requirements for polishing grains varies depending on the intended use of the koji of course. Koji used to make sake has a stronger focus on sweetness and thus is normally highly polish. Koji for cooking however, typically emphasised the savoury taste over sweetness, which would mean less polishing. This is because the savoury umami taste comes from the breakdown of proteins, which are mainly present in the bran of the grain, which can be easily polished off. For this same reason, the barley on which we grow koji on at Noma is pearled barley, which is whole grain barley that has had its hull and removed and bran layer polished off.

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In order to start cultivating koji, you either need to start with some live koji which you allow to sporulate, or buy koji spores. Koji spores or Koji tane (種麹/麹菌) are sold in Japan in two forms. One is as rice that has already been inoculated with koji which is typically brought by people wanting to make Amazake at home, and spores in powdered form (which is much harder to find). I know this isn’t really helpful but the easiest way to find koji spores yourself is to search it up on the internet. Storage wise, koji spores stored in an airtight container can be frozen for a couple of years. Rice inoculated with koji is also available in two forms, rice that has already been dried after inoculation (common and refrigeration not needed) and inoculated cooked rice (rare and requires refrigeration). To propagate koji from these rice, the easiest method is to blend or grind the rice and sieve the powdered koji rice onto fresh rice. 1g of koji spores should be enough to inoculate 1kg of rice.

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In Japan, koji is typically cultivated in cedar trays which are never washed and constantly reused. This means that over time, Aspergillus oryzae actually starts to live in these trays. This also occurs in the traditional wooden barrels used to make miso and soy sauce. Any tray or container that has ample air circulation also works. In this article I’m using the shallow cedar trays that were used to store sea urchins before that. Perforated trays work best as they allow air circulation underneath as well.

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The three factors vital to control in order to grow koji successfully is oxygen, humidity and temperature. Their optimal states are:

- Plentiful oxygen flow

- 70% to 75% relative humidity

- 30°C (above 45°C the koji is unable to survive)

At these specific conditions, the koji will be fully matured after 48 hours. It is possible to start to smell the fruity aroma of the koji after 24 hours of growth, with its taste fully maturing after 48 hours, transitioning to a more savoury taste. In my personal experience however, if the temperature is lower or the other conditions are not optimal, it can take up to 4 days for the koji to fully mature. In that respect, the fact that it was possible to consistently grow koji on a 2 day cycle at Noma almost every day of the year in no small feat. If grown in too humid an environment, it can start to develop off flavours that is not unlike that of damp cardboard. Wet spots on the tray also might facilitate mold growth which would be dangerous.

Oxygen and airflow is important because the breakdown and absorption of nutrients is powered by aerobic respiration (which requires oxygen), which then also produces heat. Airflow allows this heat to dissipate while providing oxygen for the koji. The internal temperature of the koji can very easily reach the lethal temperature of 45°C if there is insignificant air circulation. The lack of air circulation may also cause a buildup of carbon dioxide pockets which may promote mold growth.

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A relative humidity of 70% to 85% in Japan from June to August is not uncommon but otherwise, an artificially humid environment needs to be created. The best way to measure the humidity of a room would be a humidity meter but that’s actually not necessary at home. A humidity of around 75% is characterised by a small amount of condensation that doesn’t form into a pool. A damn towel should also remain at the same dampness when the humidity is just right (doesn’t dry out or increase in wetness). In order to maintain this humidity, it helps to have a confined space with a body of water which maintains the humidity through evaporation. Something along the lines of a 63 litre storage or small unused fridge works best. At my kitchen, I gently covered my trays with a damn towel and placed the trays in a small room with a large tub of water. I then heated the room with a standard winter room heater.

How to grow Koji (麹):

At each step, I will describe the processed that I personally used at home, while adding the process that we used at the restaurant in the notes. I grow koji on both white rice and brown rice here. As described above, the process for growing brown rice took an additional day as the koji grew much slowly compared to white rice.

1. Wash the rice in water three to four times until the water runs quite clear. This removes any excess start on the grains which will cause the koji to grow too fast, causing them to have produced an insufficient amount of enzymes needed to produce a pleasing taste.

2. Cook the rice in a rice cooker as you typically would but adding slightly less water. I am lucky enough to have a rice cooker with a softness to hardness scale ranging from 1 to 5, with 3 being ‘normal rice’. In this case, I just used the number 4 setting (slightly less cooked).

3. Line your cleaned trays with damp towels. If using a wooden tray you do not need to line the trays with towels but a just about damp tray helps.

4. Once the rice is cooked, spread out rice in a tray and allow to cool to body temperature. Adding the koji spores to hot rice would instantly kill the spores. When spreading out the rice, be sure to separate the grains gently to allow ample air circulation without crushing/mushing the rice. Cover the rice with a damn towel to prevent the rice from drying out. Alternatively you can allow the rice to cool in an ohitsu rice container (お櫃), which is a cypress container that allows you to store rice without it drying out.

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5. If using spores, make a small cut on the packet and gentle tap out the spores over the grains. Only a small amount is needed. Mix the rice together to evenly spread out the spores before adding a second application of spores and mixing again. If using koji rice, blend the rice into small bits in a food processor or hand blender and pour into a tea strainer. Tap the tea strainer over the rice in the same way as you would the spore packet.32754116897_4f3cffdad5_k

6. Cover with a damp towel and place in your fermentation environment for the first 24 hours. If using a perforated try, do not cover the holes by letting it sit directly on a surface but prop it up instead.47644241612_4eeae7f654_k

7. After 24 hours, you should be able to see a small amount of white fluff growing on the rice- the first signs of growth! Take out the tray and gently separate and mix the grains back together to promote even growth and air circulation. Ferment for another 24 hours.

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- After the next 24 hours (48 hours in total), the koji is ready to be ‘harvested’. If not using immediately, transfer to containers and store in the fridge for up to 5 days. Alternatively, freeze for up to 3 months. After the first 24 hours, the koji growth would have reached a so called “critical mass” and will start growing extremely fast. It is at this point that the koji is most likely to overheat. If you notice the temperature getting to high, try to ventilate your fermentation environment by leaving the container or door open and if really need be, re-mix your rice.47663662042_cd73c24923_k (1).jpg

Notes:

- At Noma, we soaked the barley in the fridge overnight in order to fully hydrate the grains before steaming, making it easier for the koji to grow on the barley.

- Cooking grains in a cooker typically results in overly wet/mushy grains that were not optimal for koji growth and thus we always steamed our grains. If steaming your grains, steam until there is no more white in the centre, around 15 to 20 minutes. We used a Rational Brand combination oven in the kitchen.

- We used to separate the grains when they are still hot as they tended to clump together as they cooled. I used to wear a double layer of latex gloves before using my hands to do this.

- Using ground up koji rice has less spores than pure spores and some of the powder will just be rice. Therefore a larger dusting would be needed.

- After the first 24 hours, we furrowed the grains in the tray into three rows to allow for greater air circulation and heat removal. This is required when making a large amount of koji as heat generation can easily get out of control. I was only making a small amount that could easily be arranged in a thin layer at home and this step was therefore not necessary.

- We actually keep the koji refrigerated for a few days before freezing it as the enzymes continue to work on the rice even if refrigeration slows down the growth of the koji. This means that it’s taste will actually slowly increase up to a few days in the fridge.

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On harvesting spores for the next generation

In the same way that it is possible to keep a sourdough culture going for many generations, it is possible collect spores from your previously cultivated bath of koji for future use. We tend to harvest koji after 48 hours because it is at this age/maturity at which it is the most flavourful. As you let koji continue to grow, it’s flavours start to become stronger and more pungent. If you continue to let your koji grow however, it will soon start to sporulate. If you want to harvest spores, start of by taking 48 hour old koji rice and separating them into individual grains on a tray as best as you can. This maximises the surface area of grow of the koji which in turn maximises the amount of spores that you can harvest.

As with before, cover the container or tray with a lightly damp towel and return to your fermentation environment. Continue to grow for another day and a half (around 36 hours). After this period of time, your grains should be even fluffier than before and should shed powder if gently touched/agitated. This powder is the spores of the koji. To dry the grains covered in koji spores, remove the damp towel from the tray and remove the source of humidity. Allow to dry until hard before storing in the freezer (around 2 days).

Basic Safety Measures

The best safety measure against mold/bacteria growth and infection is just some basic common sense. We as humans have a remarkably good intuition when it comes to judging whether food is safe to eat or not. If the food doesn’t smell edible or smells slightly off then chuck it out. Properly grown koji should smell sweet and not pungent. Its colour should also be a nice vibrant white or sometimes slightly yellowish colour. Any black or blue colours means that something has gone wrong (and so you should throw it out). The tray you use to grow your koji should also be washed clean and the towels that you use to cover the koji should also be washed. At Noma, we had temperature probes that we inserted into the inside of the rice in order to monitor the temperature and we usually wiped the probe with alcohol to sterilize it before inserting it. A completely over the top sterilization of everything is unnecessary and just basic kitchen hygiene goes a long way.

What Koji needs to grow and how to provide for its needs

- 04/05/2017

- 107 Comments

This article sets out to explain what conditions are necessary to grow Koji and how to generate these conditions. An article on the time frame of growing Koji will follow soon.

What always irked me about instructions on how to grow Koji (and how to make miso) is that they always explained it in a step-by-step way, rather than explaining what the essential factors are in the whole undertaking. I.e. the instructions said “use hot water bottles”, “use x amount of towels on which to let the rice cool”, “set up a bowl of water in the incubation box” etc. but not what the purpose of those actions was.

So, here I will try to summarize what Koji likes, because there are many ways to generate the necessary conditions.

What Koji needs

Pretty much every instruction says that Koji needs temperatures between roughly 28°C and 36°C (and they are right, of course). If the temperature is around 40°C the fungus starts producing spores earlier, which is not wanted almost all of the time). If the temperature is even higher the fungus will die.

Koji will produce more amylases at higher temperatures, and more proteases at lower temperature. So, depending on whether you make sake or miso you can adjust. For the beginning don’t worry about it so long as you are within 28°C and 36°C.

Koji also needs a high relative humidity. In the beginning, the first 24h, 90% are desirable. It’s no catastrophe if it’s 80%, or even 70%, but it certainly works better at 90%.

Some people say that after 24h it is better to lower humidity again, so that the fungus has to burrow deep into the grain in order to find water. If the air is always very humid the fungus can just happily grow on the outside without actually growing much into the kernel. I think there’s truth to that, but I am undecided on how much this is going to affect the amount of enzymes that are produced, which is the whole point. This is an experiment waiting to happen. :)

The Substrate

Many foods can be used as a substrate for Koji. Usually people use rice, barley or soy. If I write “rice” in the following paragraphs it also applies for all other substrates.

The rice should be:

- Not too wet

- This is why in all instructions it is heavily recommended that the rice is steamed, after it had been soaking for 12 hours (Barley should soak for 2-4 hours.)

- Some even recommend keeping the rice in a sieve for 2 hours prior to steaming, to get rid of as much water as possible.

- In a pressure cooker steaming takes about 20 minutes from the point at which it reached full pressure. In a normal pot it takes about 40 minutes.

- For steaming, a piece of cloth is very helpful to keep everything together.

- After steaming, the rice/barley should be spread on a layer of dry cloth or just on a clean table in order to cool down and dry. A lot of moisture will steam off and some will soak into the cloth.

- Steamed rice will seem strangely dry, don’t worry, it is supposed to be like that. When eating it, it will seem a bit gummy.

- Why it should not be too wet: If your rice is too wet you are making it hard for Koji to grow, and easy for bacteria (mostly Bacillus) to grow. You will notice as there won’t be much, if any, mycelium visible. Instead there will be a smell of ammonia. To get the water content of your rice perfectly right, you have to steam your rice. Cooking it will not work.

- Dehulled/polished:

- The rice should be white, not brown rice. Same goes for barley, it should be pearled barley, if the hull is still there the fungus can’t penetrate the kernel and nothing will happen.

- Some people do grow Koji on natural rice, but they sprout the rice first. Anyway, if you grow Koji for the first time it is strongly recommended to do so on white rice or pearled barley as they are much easier to work with.

So this is pretty much it. The substrate part is pretty clear, so now let’s talk about the many ways to provide for heat and humidity.

How to provide for it needs

There are as many solutions as there are people making Koji.

Solutions without special equipment

At the most basic, some people use hot water bottles and towels to provide warmth for their Koji, changing them when necessary. Personally that’d be a bit too much of a hassle for me as I like to sleep at night. If you go by that route, there are very helpful thermometers with probes out there that can sound an alarm once temperature goes below or above a certain threshold – this might be helpful with other devices too.

A variation on the hot water bottle theme would be to put canisters/pots with hot water in an insulated box. An insulated box could be everything from one made of carton wrapped with blankets to special thermoboxes.

I am always in favour of using solutions that don’t require (too many) extra purchases. However, if you feel positive that it is going to be a lasting hobby, why not spend a bit of money on it. Or maybe you already have one or more of the following devices:

Solutions with “special” equipment

I have heard people have good experiences with bread proofers, which makes sense because sourdough/yeast like the same temperatures as Koji. By the same token I think there are bread baking devices out there which are meant to do every step of the baking process – if they are tweaked to do just the proofing they might be a good solution too for small batches of Koji.

Another device that seems perfect is an incubation box for chicken eggs. Somebody in one of the miso groups on Facebook talked about it, and it struck me as quite genius, since these boxes (well, the better ones I suppose) not only regulate temperature but also humidity. They can be cheap too – starting from 50€ and you are good to go.

I am sure there are plenty other options out there as well. Stuff that is used for terrariums or aquariums may be very helpful. Heating blankets may be an option too. One person I know makes perfect Koji just with a heating blanket. Ceramic heaters can be used to heat the air in a box. I have used a hair dryer for that purpose too, and it worked quite well! (It just was a bit loud every now and then)

Obviously, for some of these heat sources you will need a temperature regulating device. I use an Inkbird ITC-1000, which works quite well. It comes with a temperature probe, which I usually put directly into the rice. This is better than just regulating the temperature in the box, as the Koji will produce its own heat after some time. For this reason, after the first day, usually no heating is required anymore!

Be creative with your solutions, but make sure to stay safe. My first Koji box was made with floor heating wire, and I think it was not a safe option as the insulation of the wire once melted. Making Koji is fun, burning down your home is not!

Providing humidity

A simple way to provide humidity is to just spray the insides with water every now and then. You can also spray the cloth you are growing the Koji in (as in the photo below, in the tray section).  Probably much better to try this before spending money on a solution that works maybe marginally better than another.

Many people just put a baking tray with water over their heating element. Usually humidity will go up to 70% with that method – which is OK. It helps to put hot water in the tray in the beginning to raise humidity beyond that.

The super fancy solution, however, would be to use a humidifier. These devices are made specifically for humidifying air – perfect. Ultrasonic humidifiers work best. There are devices out there that will switch the humidifier on or off depending on relative humidity – usually they have a temperature controlling option too. The WH8040 is said to be good – it just regulates humidity, however.

I’m sure there are other solutions for humidity out there as well. If you have access to a professional kitchen you might hit the jackpot and there might be an oven that is able to regulate temperature and humidity at levels required for making Koji.

Cory Hughart commented on this article that there is another really easy way to regulate humidity. If you are using an unperforated stainless steel tray (preferably a deep one) as they are common in commercial kitchens, you can put your Koji in the tray and cover it with plastic wrap. Put some holes into the wrap so that your Koji still gets some oxygen. I would also advise to still use a piece of cloth between the tray and your Koji, so that no water is going to pool in the bottom of your tray. More on that in the next section.

Trays for Koji

One thing that really changed the quality of my Koji was the switch from a baking tray to one made of wood. The baking tray obviously didn’t soak up excess water, so the lower layer of rice sometimes got a bit soggy – not good.

I strongly recommend to incubate Koji in a wooden tray. Not only because of sogginess issues, but also because the wood will help regulate the humidity in your box. However, if you don’t have a wooden tray and it’s not easy for you to make one, you can still get some cloth and put two layers of thin cloth or one layer of thick cloth on the bottom of your baking tray or pyrex dish.

(edit March 2019: In the meanwhile, I tried perforated stainless steel trays in conjunction with thick cloth, and it worked quite well too – the key here is to avoid any pooling of water/moisture)

Traditionally in Japan, cedar wood is used for trays and Koji boxes (the boxes, sometimes even rooms, are called “Muro” there). Here in Austria, cedar is hard to get and expensive. In my opinion it’s probably best to use woods that are used in building saunas. So the obvious choice is spruce. It’s cheap and widely available.

Usually trays are made without metal, just with wooden joints. I was a bit lazy with mine and used screws. I don’t see a downside, except that my tray looks less fancy than it could.

Examples of Koji boxes (aka “muros”)

My first setup

Here is was using a dehydrator with a temperature control device. This is not because I think a dehydrator is inherently better, it’s just that I already had one. I put it in a cabinet as shown below.

Doesn't look too professional, I know.

This is basically an old re-purposed sewing cabinet. The wooden tray with the rice goes on top the wooden rails (more on that later). The pot you see on the right is filled with water and I put an immersion heater in it, it is there to heighten the relative humidity of the air.

Way on the right next to the box you see the ITC-1000, which regulates the temperature. It has a probe attached to it which I always place in the middle of the koji. So depending on the temperature of the Koji, it switches the electricity of the dehydrator and the immersion heater on or off.

It is set to heat when temps fall below 30°C, and to stop heating when they are above 30.5°C. I found it’s better to have a small range of temperature, because the temperature of the Koji will lag behind and the heating phase will result not in a rise of 0.5°C, but closer to 3 or 4°C, but that’s OK.

The next setup

After the sewing cabinet I moved on to a new box, as the veneer of the cabinet started to peel off and the thing got quite gross… so I built myself a box from spruce stock and spruce boards.

My current setup

You can see there are two controllers, one for temperature and one for humidity. The silver thing you see on the bottom right is an ultrasonic humidifier. On the left is the dehydrator. Meanwhile I started to use a hairdryer instead of the dehydrator, as it is small, powerful and made to resist high levels of relative humidity.

The controllers switch the devices on or off, depending on the need of the moment. The temperature probe can be put into the rice, while the probe for humidity is always at the top.

Growing the Koji

Begin by diluting the spores.

Once the rice/barley/etc. has cooled down to about 35-40°C you can spread the spores with a sieve over your grains. Mix the grains well, so that the spores are distributed well.

Line your tray with a piece of cloth and then put your grains into the tray. Keep everything at the desired temperature and humidity for 24h (you can moisten the cloth a bit by spraying some water onto it, but don’t make it too wet). I usually put the thermostat probe into the rice, to ensure that the grains have the right temperature.

After 24h I stir the rice the first time. This helps to better distribute the Koji and also to stimulate it to penetrate deeper into the kernels. If you want fancy looking mats don’t stir the rice again after this point. For better penetration of Koji into the kernels it is better to stir every 4 hours or so.

This Koji has not been stirred again after the first stirring at 24h.This Koji has been stirred a few times after the first stirring at 24h.

When is the Koji ready to use?

The time it takes for your Koji to be ready depends on the type of grain you are fermenting, and also on the strain of Koji you are using. Red rice Koji is ready after 40 hours, in my experience. Barley Koji can take 50 hours or longer.

In any case, if you see that your Koji is producing yellowish green spots, it is starting to produce spores. I recommend stopping the fermentation immediately by cooling the grains either in your fridge or outside if it’s cold enough. Be aware that the Koji may still be producing its own heat, so spread it out. I once just put the tray  into my room to stop the fermentation and after a few hours I came back to some really green Koji.

Heavily sporulated Koji tastes quite bad. It has a strong off-taste and if you make miso with it, the miso will discolor when it gets into contact with oxygen. It does not look good. Don’t worry if there are some yellow/green spots. It only gets problematic if everything is really green.

So the best moment to stop the fermentation is just before it starts to sporulate. I understand it is not so easy to tell when that moment is. It’s best to check your Koji quite often, especially when you make the first few times. With experience you will get a good intuition of when your Koji is ready.

Thanks for reading! If you have any critique, input or questions, please let me know!

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THIS POST HAS 107 COMMENTS

1. Dylan Reece

12 MAY 2023 REPLY

Hello Viktor and thank you for the valuable information.

I have grown my first batch of Koji on basmati rice using light rice koji spores. The resulting product smelled strongly of fresh mushrooms. I made Shio Koji and used 5% of salt. After three days fermenting, and stirring twice daily, a strong blue cheese aroma has developed.

Having never tasted/seen/smelled koji or shio koji before, I am trying to work out if I should be happy or sad at this point!

Many thanks

1. Viktor

16 MAY 2023 REPLY

Hi Dylan,

a strong smell of fresh mushrooms sounds good. Koji can smell like anything between that and fresh fruit (especially apricot and exotic fruit, imho).

A strong blue cheese smell in shio koji is a bit weird, however. That usually only happens when combining koji with dairy.

Did you make a 5% brine or is 5% the total amount in the shio koji? If the 5% is the brine, your shio koji now has much less salt in total, which could also explain the off-taste.

If you have 5% salt in total, and your koji was nicely grown and had no strange spots, you are on the safe side in terms of food safety.

2. Maarten

19 APR 2023 REPLY

Hi Viktor,

My koji always starts to sporulate and become green around 36 hours. What can be the reason for this? Too much humidity? Too less airflow? I have temperature quite right.

1. Viktor

20 APR 2023 REPLY

Hi Maarten,

it depends on the kind of koji you are making. It sounds like you are either making soy sauce koji or barley koji.

In the case of soy sauce, it is a sign that the koji was a bit too hot. However, sporulation is quite normal, and not a problem. We are always making our shoyus with sporulated koji.

In the case of barley koji, it is a sign that the barley was either too wet, or it got too hot. I doubt it was too little airflow.

As soon as you see signs of sporulation, make sure to remove the koji from the muro and cool it down to stop the growth.

3. Wilfried

14 FEB 2023 REPLY

Hi there! I would like to said that you have wonderful website and lot of useful information. Thanks for that. Due to you, i started to try to growth koji first time. After 30 hours at 35 to 28 °c the koji tart to show up on the rice but it’s really stinky. Maybe ammoniac. Is it safe to use it or not? Should i trhow everything?

1. Viktor

14 MAR 2023 REPLY

Hi, if your koji is really stinky, you should throw it away. It is a sign of bacterial infection, which happens when your rice is too wet.

4. Silviu

23 OCT 2022 REPLY

I just wanted to share here the process by which I recently managed to make rye koji. My first attempts weren’t successful, because rye has a thick bran layer that prevents the koji-kin from penetrating the grain. After reading a bit, I decided to crack the rye grains to get around this problem. I used a grain mill set to very coarse (the same setting I use for cracking wheat for shoyu) and passed the dry rye grains through it, twice. The goal was to split in two or three each grain, and it worked well. I sieved off any fine flour generated (which was less than 5% of the initial rye weight). I left any coarse bran that had detached from the grains in, because I think it provides a lot of the rye flavor, and shouldn’t hurt anything once it’s detached from the grain. I then soaked the rye and steamed it (rye soaks and steams quite quickly, like barley: 1h soak, 30min steaming time), inoculated it with spores and let it incubate as usual. I got very vigorous growth and a beautiful koji at 48h.

Just wanted to leave this here in case anyone else wants to use rye for koji. I like rye a lot in baking, and I can’t wait to find out how the miso I made with this rye koji will taste.

1. Viktor

23 OCT 2022 REPLY

Hi Silviu, thanks a lot for sharing your experiences here! Very appreciated.

5. Ronny Staquet

24 SEP 2022 REPLY

Hi :-)

I searched on Google and read here, but i don’t find this information : do koji spores need total dark obscurity to germinate and grow, or is koji not bothered by light ?

I ask because I’m going to use a small plastic greenhouse of 50x40cm, electric heated built-in device and precisely thermoregulated, but with a transparent roof.

Must I cover it or keep it in the dark for good results ?

Thanks.

1. Viktor

24 SEP 2022 REPLY

Hi Ronny! Light doesn’t bother koji. Maybe it would be bad to put it in direct sunlight, but everything else is no problem at all.

6. Lennart

18 SEP 2022 REPLY

Hi Viktor! I have been making koji for years but encountered something strange for the first time: underneath the white layer of koji (after 30 hours or so) became completely brown. The taste is actually not bad, a bit of the sour off-notes that the green sporulated koji has but nothing horrible. Have you had this before? I noticed that the last hours the temperature spiked from 29 to 35 degrees, a bit more than what normally happens…

1. Viktor

20 SEP 2022 REPLY

Hi Lennart, that sounds like the bottom got a bit too wet, and you got some bacterial growth there (hence the sourness from lactobacillus, presumably). Was it slimy too?

7. Joris

10 FEB 2022 REPLY

Hi Viktor

I am making Koji for the first time and after 46 hours right now i don´t smell anything sweet but more smokey notes. The pearl barley made a nice cake and everything sporulated according to plan only the smell seems to lag behind. My setup is a plastic container with a layer of water in it and a aquarium heater set on 30 degrees celsius. The towel under the pearl barley remained damp during the whole process and I covered the lid with another towel so that condens would not fall in the tray. I was wondering if I can use this batch or not? thanks in advance for your answer!

Kind regards

Joris Holleman

1. Joris

10 FEB 2022 REPLY

An now that I smell it also a bit like wet laundry which stayed too long in the washingmachine. Thanks again!

2. Viktor

14 FEB 2022 REPLY

Hi Joris,

it is always hard to say without photos. It sounds OK, but I can’t say without photos. Sometimes people expect a stronger smell, but Koji can have a rather subtle smell too.

The koji should not sporulate, if you intend to make miso with it. For soy sauce it doesn’t matter, but for anything else, the koji should not sporulate. I recommend to pull koji after about 40 hours.

8. clara

4 OCT 2021 REPLY

Hi Viktor, do you have any experience with growing koji on millet or buckwheat? If so – did you soak and cook it? And how long? I’ve tried with soaked, cracked buckwheat – it was directly super wet and slimy and before trying to grow koji on it, I knew already it most probably wouldn’t work. Haven’t tried again since

1. Viktor

3 NOV 2021 REPLY

Hi Clara,

I don’t have much/any experience with these substrates. You were already on a good track by using cracked buckwheat. As with anything koji, the art of making it lies in getting hydration right. This is especially hard when your substrate is very small. I would recommend to try the cracked buckwheat again, but this time don’t soak it. Instead, weigh how much you have, and then mix in half the weight water. I.e. if you have 800 g of cracked buckwheat, mix in 400 g of water (or 1 kg buckwheat-> 0.5 kg of water). Let it absorb the water and then steam it. This should be much closer to ideal hydration.

I tried millet once, but I found that the shell is quite hard, and so koji has a hard time penetrating it. But I am sure it is possible, as I know there are people working with millet and koji.

9. Scriabin

18 APR 2021 REPLY

Hi Viktor,

Thank you for this post! It helps me a lot with my first trial of amazake making from Koji.

Initially my amazake has quite strong koji-like aroma when it was done being kept for the enzymatic hydrolysis part (i waterbath it for 16h at 57-59’C). However i inactivate the enzyme by shimmering it for 10 mins, and the koji-like aroma also gone, leaving only rice smell.

I have one question: on the final amazake that I made, there is kind of, something gel-like like nata de coco kind of texture. Im not sure whether its from polysacharide or from aspergillus’ mycellium, but its weird to have something chewy in amazake… theres no off flavor or off taste, tho. Do you have any suggestion or susceptible cause of this?

1. Viktor

21 APR 2021 REPLY

Hi Scriabin,

you don’t need to get rid of the enzymes in the end, so if you don’t cook the amazake afterwards, maybe more of the koji aroma will stay.

I am pretty sure the gel-like texture is a result of the starch being cooked. I like to make amazake-puddings this way. Again, if you don’t cook it afterwards you shouldn’t get this.

10. anastasia

13 APR 2021 REPLY

Hi Viktor,

I am wanting to use these spores for a design project where i am looking at pigment producing microorganisms. I was wondering if these spores will produce pigments and if so, what sort of conditions I would need. Your page has already been very informative and it is clear you know your stuff! look forward to hearing back from you.

1. Viktor

21 APR 2021 REPLY

Hi Anastasia,

I don’t think Koji is very suitable for pigment production. In this case I would look into bacteria and algae.

11. Alberto Coppola

5 APR 2021 REPLY

Could i make the started with Koji rice ? How much Koji rice do i need per gram of rice ?

Thank you !

1. Viktor

6 APR 2021 REPLY

Hi Alberto,

while in theory that’s possible, it’s not recommended as it is not very reliable or safe. In the process of making koji rice you may introduce other microorganisms which you don’t want in your koji. So it’s better to start off with a pure starter.

12. Anne

24 MAR 2021 REPLY

I have just finished my second batch of koji using light rice koji spores. My setup is quite simple. I use a seedling warming pad, a wooden tray (filmed under bottom and over top) and a big folded towel for insulation. My only investment has been a steamer.

I used my ricecooker for the first batch, but the rice were to dry. The result was 50 % koji, 50% dry rice.

Second batch was steamed. Result > 95% koji. I think, I will supply some extra moisture next time with a damp dishcloth under the top film. The edges were a bit dry.

I have used the koji for amazake and shio koji (both taste very good) and miso (to be tasted in a couple of months).

1. Viktor

6 APR 2021 REPLY

Hi Anne,

happy to hear that you figured out a nice way to make koji :)

13. Oliver

30 NOV 2020 REPLY

Hi, I am planning to do both sake and shoyu. I am fairly confident that I understand about the initial stages, where the koji needs a little air flow to provide oxygen. What is less clear to me is whether the mould stays alive for the subsequent stages, or whether its just the enzymes (amylase for sake, protease for shoyu/miso) that remain active? Should the containers be sealed/airlocked or kept open (cheesecloth with a rubber band to deter insects)?

1. Viktor

30 NOV 2020 REPLY

Hi Oliver,

once you start making something with the koji, it will die. So just the enzymes will remain active. I would advise against airlocking your shoyu, as you need to stir it often. The mass of wheat and soybeans will float up like a sponge because of all the CO2 that’s produces, and you need to push it down every now and then. I recommend to stir every day for the first two weeks. This also helps to prevent wild mold growth, as the surface is disturbed every day. After these two weeks, your shoyu will have a lower pH, so the likelihood of mold growth will be less, and you can start to stir every two to three days. Stirring also brings in oxygen, which will help with darkening the sauce. In between stirs, I just put a lid on, but you can also use a cloth with a rubber band.

I have never made proper sake, so I am not sure how it works there to be honest.

14. stergios

27 NOV 2020 REPLY

with wich instrument do you arrange the temperature?i havent understood.i just have recieved your koji spores and programming my equipment.if you could help little more!

the miso poppyseeds btw was supertasty!!!

1. Viktor

27 NOV 2020 REPLY

Hi Stergios,

I recommend to get an Inkbird ITC-308. It is already wired up and user friendly.

Happy to hear you liked the miso!

Greetings,

Viktor

15. Nick

7 NOV 2020 REPLY

Hi Viktor, thank you for the thorough explanation of how to grow koji. My question is how to keep the rice from overheating in hot weather. Even when I break up and stir the rice, after about 30 hours it’s generating so much heat that it quickly climbs back towards 40 degrees. I’ve tried floating the tray in a container of ice water but it’s a bit difficult to get the temperature right. Any suggestions? Normal daily temps here are 29-35 Celsius (great for the first day of incubation, but not after)

1. Viktor

16 NOV 2020 REPLY

Hi Nick!

That’s quite warm ambient temperatures. Do you have any spot in your home where it could be a bit cooler? I think it’ll be very hard to get the temp right otherwise.

If you don’t have such a spot, it could be an idea to get a fridge, put the thermostat probe into the rice and make the fridge cool down the rice to 33°C.

16. Peter Chris

5 NOV 2020 REPLY

Hi Viktor

I wish I have found you guys earlier.

I have this strange situation with my koji. It has now been growing nicely on the steamed rice for almost a week and it is till not turning green. It is beautifully cream-white with what i can describe as crowns on top of the stalks/fiber and has been like that for a few days. the aroma is very pleasant. But, it is just not going green. Is that normal? Are there Koji types that have white spores?

It is residing in the oven with oven light on and a tray of water so the the humidity should be around 70% with around 39 degrees celsius.

1. Viktor

16 NOV 2020 REPLY

Hi Peter,

there are spores that are white! Was your starter white or green?

It sounds to me that the rice dried out, and the koji couldn’t produce spores in time.

Generally, I think it’s not a good idea to make your own spores, as it is hard to keep a pure culture in a private setting. Some foreign molds produce toxins that accumulate in the liver and elsewhere. That being said, make sure to only make your own spores once. I.e. don’t keep on propagating your propagated spores.

17. Duncan

29 OCT 2020 REPLY

Hi Viktor

I’m struggling to get strong growth on my Koji rice or barley.

I would greatly appreciate some help.

I’m either using long grain white rice (white koji spores) or pearl barley (barley spores)

I dilute the spores into 29 g sterile rice flour as suggested.

Rice is soaked over night, barley for 4 hours.

Rice is steamed in a rational oven 100C for 1 hour on a perforated tray wrapped in muslin cloth. Barley for 45 minutes.

The substrate is cooled at room temperature and is cool and dry before inoculating.

The substrate is wrapped in muslin, approx 2.5 cm thick in a gastro oven tray and wrapped in cling film with a few holes.

The tray is put into a themo box with a heat mat connected to a pid controller and set at 30c. The probe is put into the substrate.

I mix after 24 hours (have tried dampening the muslin) and leave until the full 48 hours.

The koji comes out better and at best is all chalky white with a good sweet smell and taste but no growth on top and sometimes slightly cakey.

The barley at best smells good and tastes slightly sweet but is not cakey and is little to zero visibility of growth.

Do you have any suggestions?

Thanks,

Duncan

1. Viktor

16 NOV 2020 REPLY

Hi Duncan,

please accept my apologies for not getting back to you earlier.

We usually steam our rice in the rational oven for 25 mins, it’s long enough. 45 mins for barley is good! I see in the email that you are actually using Job’s tears? That’s what they used in Japan originally instead of barley, if I am not mistaken :)

Did you make holes in the cling film? The last customer who had trouble growing koji used the cling film method too. Once he tried without it, it worked much better. Maybe your Koji is suffocating? I would recommend to try again without the cling film, and making sure that the cloth stays damp. How high is the gastro tray you used? Maybe there was not enough air in it.

Let me know if this changed anything if you try again.

18. Mike

30 SEP 2020 REPLY

Hi Viktor! I have a brewery in Quebec and I want to incorporate koji in my sour mash. I want to do a starter with my pure koji. This is my questions.

– Can I use malted barley with koji to do my starter?

– I saw that some brewers( they are not a lot and there are not a lot of information on it) that use Koji Rice in their sour mash (lactobacillus production to get lactic acid) at 65 celcius to accelerate the process.

– Which kind of acid the Koji secrete (lactic acid???, kojic acid?? )

– The koji is aerobic or can be anaerobic

– Do you know the Ph of the koji rice at the end approx

1. Viktor

8 OCT 2020 REPLY

Hi Mike!

You can kojify barley malt. Maybe you will have to crack the barley a bit since Koji can’t grow through the hull.

Strictly speaking, Koji Rice does not have much to do with lactobacillus. With Koji Rice you are supplying additional sugars and enzymes.

Normal Koji does not produce acids in quantities worth mentioning. But you could try to use Aspergillus Luchuensis – it produces citric acid. So you could make a sour mash with it, which would have a more fruity touch.

Koji is a mold, so it needs to breathe oxygen in order to be able to digest all the sugar and amino acid it is eating :) if you put it in a closed thing, it will suffocate. You can really smell the CO2 when you do that.

I don’t know the pH, sorry. My guess would be around a pH of 6.

For your application, I would kojify pearled barley with A. Luchuensis and use that. Making a mash with pearled barley only is problematic for lautering, but as a supplement I can imagine that it’d work quite well.

If you prefer to have lactic acid instead of citric acid, it’d be probably best to look out for lactic acid bacteria for beer. I am sure it’s possible to buy pure cultures.

Hope that helps!

19. Michel

7 AUG 2020 REPLY

Hi Viktor,

This is my first time making koji.

Im currently at 64 hours in my koji rice fermentation.

I haven’t seen the white mold fiber forming other than really small pieces.

It smells really alcoholic now and has this broken white/ darker yellow with no sign of mold any where.

I stirred every 12 hours and the temp kept rising to 40 degrees Celsius.

I don’t know if its bad or still usable.

Can you help me?

1. Viktor

7 AUG 2020 REPLY

Hi Michael,

you should see white stuff at around hour 24. It sounds to me that your substrate is too wet. Can you please send me a picture to office -at- fermentationculture.eu?

20. Catherine

5 AUG 2020 REPLY

Thank you for sharing your thoughts and experience regarding koji rice. There is actually this guy on YouTube that showed how to make your own koji-kin from koji rice. https://www.youtube.com/watch?v=tE1-Q0wskfk&t=521s He let it spore until it’s totally green, and then he powdered it. He said it’s related to the white koji-kin. However, you mentioned that the greenish spores have an off taste. I’m pretty doubtful myself, and I’d like to hear your thoughts on this.

1. Viktor

6 AUG 2020 REPLY

Hi Catherine!

My honest thought on this topic is that it’s not worth it to propagate your own spores, the risk far outweighs the gain.

I know what many people may think when I say that, “of course, you sell them after all”. So, I may be in a bit of weak position to make my point, but I wouldn’t ever propagate my own koji.

The problem is that nobody can work cleanly enough at home to ensure that no other species takes hold. Maybe it’s safe to do it one time. But it’s definitely not safe to keep on propagating your own culture, as other species may take hold.

Many molds produce powerful toxins, which do not poison right away (which causes people to think it’s fine), but the toxins accumulate in vital organs, causing cancer years down the line. Many people underestimate this problem. Saving a few euros is just not worth the risk to me. Also, the rice or barley also cost something + the work involved.

Apart from that, the propagation will change the behavior of the starter, as genetics change.

Also, when propagating, the rice is not powdered afterwards, the spores are sieved off the rice.

Greetings,

Viktor

2. Johann Bouché-Pillon

28 AUG 2020 REPLY

Hi Viktor and thanks for the fast delivery of the white koji spores !

I made my first attempt with a. Oryzae on pearl barley that last week.

all looked great after 48 hours (I pushed the humidity to 80, 85 % as the grains looked a bit dried at the beginning, even then on the top) and the temperature moved from 30 to 38 degrees during the last 24hours. I just mixed the barley one time after the first day. The mycelium had a really early and great development.

My problem is , after tasting it at hour 48, there’s absolutely no taste in it, no sugar or simply not any aroma.

i cut the culture in half to let one part in the fridge and decided to pushed the other in same conditions to see what happens.

Finally the part I put to the fridge failed, it just taste like plastic.

The other part that i let 12 more hours in the fermentation room was finally better even if the « Whooa » effect were not really there.

I took some fresh grains that I mixed grossly to marinate shio, and that was still weak in term of aromas. Not zero but not crazy. I dried quickly the same grains from the marinade to grill them in oil then, and that was finally and strangely pretty great.

Then I put the main part to dehydrate and it smelled strongly something like cheese or mushrooms when i mixed it to powder, but then again the aroma was a bit low when I tried a bouillon with it. (And I put a lot).

I would love to know your opinion about it, as a beginner i’m a bit lost in my conclusions, i thought It could come from a barley which is not enough polished or a problem with low humidity

thanks a lot,

Johann

1. Viktor

30 AUG 2020 REPLY

Hi Johann,

it is hard to judge the quality of a koji without pictures. To me it sounds like you were expecting an explosion of taste, but the taste of koji can be quite subtle!

Generally, I think koji shouldn’t take longer than 48 hours. If the koji tasted like plastic, I would say it’s the fault of whatever you put the koji in.

If it smells like mushrooms that’s a good sign, but it shouldn’t ever smell like cheese, that’s a sign of a bacterial problems.

Greetings,

Viktor

1. Johann Bouché-Pillon

28 SEP 2020 REPLY

Thanks a lot Viktor , as it was my first try, I think I was simply too much around the box to disturb the process^^

All is going well now,

Greetings, J

21. Filippo

22 MAY 2020 REPLY

Dear Viktor, thank you for your article!

Since three weeks I am experimenting to make Barley Koji. I have Koji spores, pearl barley from seeberger, and I made a nice fermentation chamber out of wood, equipped with a thermostat and humidistat, a little humidifier from beurer and a little bathroom heater.

The first two times my main error was to follow the times badly (from another tutorial) and letting the Koji grow a lot of spores (24h longer time!), that produced bitter green koji… and very separated koji.

I just finished my third try, after more research: the Barley soaked maybe a bit longer (short night), then steamed 30min. nicely (was chewy), inoculated at 30 in a stainless steel tray (with holes on the bottom and a lightly damp cloth), first 24h at good temperature and humidity (30° / 75%-80%), when I took it out for the first stir it was looking nice and quite white (not completely), with a fruity smell and quite bound together… I broke it apart and put it in the chamber again. During the following 24h the temperature went up more at first (34’max), humidity also a bit higher (85° max), and the smell developed further (the fruits sweeter almost too ripe, and a somehow cheesy smell – by hour 36 ca.). When I took it out today (after ca.46h from inoculation)… the aspect/color was basically the same as 24h earlier, but the barley didn’t bind together at all, I barely saw a clump. and the smell was decreased… I tried it and the flavour is “boring” really, nothing interesting going on.

I have never tasted Koji before so I am a bit running blind… what should I try doing different next time? Why could it be that it is

always so “separated”?

Every hint, suggestion, recommendation is very much appreciated…

Thank you again for your site, best regards. F

1. Viktor

29 MAY 2020 REPLY

Hi Filippo,

It sounds like you are doing quite well already. To me it sounds like the koji dried out in the last 24h of your process. The measurements of the humidity can be a bit misleading, as the sensor also picks up on the humidity that is leaving your koji :) so it’s drying out but the sensor thinks everything is alright.

I would suggest for your next batch, to put a damp towel also on top of your koji (and make sure to keep it damp), and don’t stir it this time, then you should get a nice mat. Also, I think the ideal time to pull your koji is at about h 40-44, I wouldn’t leave it any longer.

Hope this helps!

22. johannes

11 APR 2020 REPLY

Hallo Viktor, irgendwie ging meine frage nicht durch denke ich.

Denkst du es ist möglich in einem Konvektomaten Koji zu fermentieren, da könnte ich Temperatur und Luftfeuchtigkeit genau einstellen.

Und denkst du weiters es is möglich dinkel, roggen oder gestern koji zu machen.

vielen dank, lg

1. Viktor

16 APR 2020 REPLY

Hallo nochmal,

wegen dinkel, roggen und gersten koji: Gerste funktioniert bewiesenermaßen ganz gut zum Koji machen :) wichtig ist halt, dass es gerollte Gerste ist. Dinkel und Roggen funktionieren sicher auch, aber auch die müssen gerollt sein. Das Schwierige ist da immer, den Feuchtigkeitsgehalt richtig zu erwischen. Gerollter Dinkel sauft sich sehr schnell an meiner Erfahrung nach.

Auch sind diese Körner oft unterschiedlich stark geschliffen, weshalb manche Gerste recht lange braucht bis der Feuchtigkeitsgehalt stimmt, während wieder andere stärker geschliffen sind und nur die halbe Zeit benötigen.

Falls du noch nie Koji gemacht hast, würde ich empfehlen mit Reis anzufangen. Da kriegt man ein sehr gutes Gefühl dafür, wie viel Feuchtigkeit im Korn sein solle (gar nicht so viel nämlich!). Beim Reis kann man weniger falsch machen. Einfach über Nacht in kalten Wasser einweichen und dann 25-30 min dämpfen. Der Reis kriegt so eine ganz eigene, relativ harte Konsistenz.

23. Zoe

10 APR 2020 REPLY

Hi Viktor,

I keep a sourdough starter and use it constantly and was curious if a koji culture could be kept like sourdough? Like, how you half the sourdough and then continue to feed it and keep it alive in order to constantly use it? Would you separate some of the koji and let it sporulate?

24. Vince

9 APR 2020 REPLY

Do you know if light affects the growth of Koji. I made an incubator from a wine fridge with a glass door and can’t seem to get consistent batches.

1. Viktor

16 APR 2020 REPLY

Hi Vince,

I am not aware of any bad effects of light on koji. In all likelihood your problem is somewhere else, but you could always just put some cardboard on your glass to be sure.

25. joh

8 APR 2020 REPLY

Hallo Viktor,

Ich haben in meiner küche einen kombi ofen, und würde gerne darin koji fermentieren, denkst du das geht, weil dort könnte ich die luftfeuchtigkeit und die temperatur genau einstellen,

ich hatte an roggen, gersten und dinkel koji gedacht,

lg johannes,

und vielen dank

1. Viktor

16 APR 2020 REPLY

Hi Johannes!

(I’ll be replying in English, so that more people can read it)

(Also, sorry for taking so damn long to reply!)

The question was if a combination oven can be used for koji-making.

I think, in regards to humidity, it doesn’t work, since these ovens make steam by heating water. That alone will heat up everything a bit too much, and the ovens are generally not made to keep such low (30°) temperatures reliably. At least that’s my experience with older models, you would have to try yours with a test run. Maybe get a thermometer with a cable to see what’s the temperature you have within the oven.

Since you seem to be working in a proper restaurant kitchen, maybe you have a holdomat? These should be able to keep the desired temperature a bit more reliably.

You could also get yourself a thermostat (like this one) and hook it up to a plate warming cabinet. Instant Muro :) This works great in my opinion.

As for humidity in the last two cases, I’d recommend going with the plastic-film technique. This works very well in my estimation. Some of the nicest, fluffiest koji I made was using this technique.

26. Laura

1 APR 2020 REPLY

Thank you Viktor, will follow your advice :)

27. Laura

31 MAR 2020 REPLY

Hi Viktor,

You right , the barley was a bit soft ,

I never made koji with rice before , what type of rice should i buy ? can i still use the barley koji or i need to buy rice koji?

Thanks

1. Viktor

31 MAR 2020 REPLY

Rice that is intended for rice-pudding or sushi works best. We always use Originario.

The barley koji will also work on rice.

28. Laura

31 MAR 2020 REPLY

Hello Viktor , need some guidance…. my first barley koji

So, for my set up

I am using a styrofoam box , seed heater mat , metal gastro ( without hole ) , ink bird temperature controller , humidity controller and humidifier and clean towels .

I soaked the barley for 24 hours , then steamed it for about 2hours until the barley was cooked .

Set up the box at 30degree and 90% of humidity

Cool down the barley until 30degree then put the barley koji ( the one i bought on your website and followed instructions on the package )

Mix it very well to make sure that all the koji is on the barley.

Put in the towel then in the gastro with 5cm thickness

Put into the box with the temperature stick in the barley

24hours passed and nothing happened…….. then i put an other 24hours nothing happened , just a nice smell when i open the box

I would like to know what mistake i made….

If you could guide me :)

Thanks

Laura

1. Viktor

31 MAR 2020 REPLY

Hi Laura,

it sounds like you are doing everything correctly, except for maybe one thing. Try to soak your barley for a shorter period, about 5-6 hours, and steam it for 1h.

Was your barley super soft, or did it still have some bite? The duration of soaking depends on how polished your barley is, but I imagine that 24h is too long either way.

Have you made koji with rice before? I recommend learning the craft with rice, because you can’t really oversoak it. You’ll get a good feeling for what is a good moisture level.

Greetings,

Viktor

29. Lorel

24 AUG 2019 REPLY

Hi Viktor

I’m using an egg hatcher that has max 70% humidity – hoping that’s enough. You mention reducing the humidity after the first 24 hours – any thoughts about how much to reduce it?

Thanks

Lorel

1. Viktor

24 AUG 2019 REPLY

Hi Lorel,

if your max. humidity is 70%, I’d recommend using a moistened dish towel to put on top of your koji. In the duration of the fermentation you can moisten it every now and then. After 24h-30h you could then stop moistening it and open the towel on top to expose the koji to the 70%rh air.

30. Mirko

19 AUG 2019 REPLY

Hi Viktor, I have read your post and they are so brilliant I came to you thanks to Flavio from Bologna that explained so well the Koji world and he introduced us your website. I hav got a question after Koji is ready, as you wrote up here, if I want to make a let’s say sake, even if you could not call like this because all the procedure and religion behind that, but if I blend let’s say Koji rice with water, could I leave it to ferment like this to create a kind of fizzy beer, or do I need to put yeast different from Koji inside that mixture?

I am asking you this because I read a book about sake and they do a kind of PARALLEL fermentazion, where they mix Koji rice water sugar and yeast? I have to inoculate with a yeast or for example I can put pieces of fruit so they can provide they spontaneous yeast?

Thank you

Kinds regards

1. Viktor

20 AUG 2019 REPLY

Hi Mirko!

Thanks for the kind words!

When I made sake, I just put the koji rice into water without blending it. I think if you blend it it’ll be very hard to filter. The starches will go into solution anyway, and you are left with “empty” rice so to say, which you then can separate much easier.

Also, I added some bakers yeast to start the process. You could also try to rely on wild yeast as you say, by adding pieces of fruit.

So while the enzymes are breaking down the sugars (in my case at room temp, probably between 15-18°C is best), the yeast is consuming the sugar and producing alcohol –> it’s, as you say, parallel.

All that being said, I don’t have that much experience with sake, all I know is that I got a rather decent result in the way I described above. If you want to go deeper into the topic, this rustic style of sake is called “Doburoku”.

Hope that helps!

Kind regards,

Viktor

31. M.ali Tajaldin

20 JUL 2019 REPLY

Hi,

Thank you for your koji breeding process in detailed.

I am living in Iran and have no access to Koji seed.if possiple it would be appreciated if you could write me procedure of Koji making without Koji seed or Koji kin.

Regards

Tajaldin

1. Viktor

13 AUG 2019 REPLY

Hi Tajaldin,

sorry for the long delay in answering you.

Making Koji without starter is very dangerous, because you can’t know what species of Aspergillus you are growing. Many types of Aspergillus produce powerful toxins.

Kind regards,

Viktor

32. Mabi

15 JUL 2019 REPLY

Hi Victor! Thanks for the reply. You’re right, I think they dried out. I need to improve the humidity in my incubator. At that time I only have a bowl of water beside the tray. I stopped incubating them at hour 48 (I didn’t see your response in time), there was already bit of matting at the bottom, but the dried grains were hopeless. I blitzed everything into a powder to use as koji flour in my home cooking, and will try again this week. Thank you again!

33. Mabi

12 JUL 2019 REPLY

Hi Viktor,

Thank you for this very helpful site! I am now on my 44th hour of making koji and while majority of the rice is white, there are some grains that aren’t–maybe the spore couldn’t attach itself to them? They are also not yet “matted” or in the form of a “cake”, and none of the sweet aroma of koji. Do I incubate longer?

1. Viktor

12 JUL 2019 REPLY

Hi Mabi!

It sounds like those grains dried out before the Koji could take hold of them. The ones that aren’t white, do they just seem dry or do they have any other color?

Usually, if it hasn’t worked by hour 44, there is little point in continuing the fermentation. Better to try again with higher humidity.

34. Dusan

8 JUL 2019 REPLY

Hi,

does posible to get koji without steam? Does that realy nesessary?

Thank you.

1. Viktor

9 JUL 2019 REPLY

Hi Dusan,

steaming is absolutely crucial. There is hardly a way around it.

35. Charles_k_k

26 MAY 2019 REPLY

Hello there viktor,

Just wanted to thank you for putting together such an informative site about Koji. As you can see I’m a newbie in this whole thing but greatly interested. I’ve just placed my first order of Koji spores and looking forward to making my firs Amazake drink and may be Miso.

charles K.

36. Philipp

14 MAY 2019 REPLY

Hi Victor,

Ich habe eine Frage, die ich im Internet nicht beantwortet bekommen habe: deckst Du den Koji mit dem Handtuch zu oder liegt das Handtuch nur unter dem Koji und oben ist offen? Vielen Dank & liebe Grüsse

1. Viktor

14 MAY 2019 REPLY

Hi Philipp,

ich decke ihn meistens schon zu. Ich mache das Tuch (ein Geschirrtuch ist besser als ein Handtuch) auch etwas feucht mit einem Wasserzerstäuber. Dadurch ist dann auch eine richtig hohe Luftfeuchtigkeit gegeben. Kann man hin und wieder dann mal checken ob es eh noch nicht ausgetrocknet ist, und bei Bedarf wieder befeuchten.

Liebe Grüße,

VIktor

37. Maria M

24 APR 2019 REPLY

Hi Viktor,

your site is amazing and very informative, thank you so much. I am super new to the whole koji concept but extremely into it.

I am looking to buy spores and give koji a go. I live in Cyprus, an island that has desirable temperatures and humidity levels for koji, but I am not sure whether I should try growing it outside?

Another thing I don’t understand is if it’s possible to multiply koji ? is there a way to make a mother koji and stop buying spores?

Also, I checked the koji products I can buy on your website: are these ready to be spread on soya beans or meat for example or they are good for spreading them on rice/barley to grow koji?

looking forward to hearing from you.

Best,

Maria

1. Viktor

24 APR 2019 REPLY

Hi Maria,

thanks for the kind words :)

I think that growing koji outside is not very easy. A stable temperature at 28-30°C is really important. This may be possible by day (in the shade!), but at night it probably cools down too much. If you are certain that you will enjoy making your own Koji and Miso, it’d probably best for you to invest in a thermostat (there are readily wired ones by inkbird) and a heating blanket or some kind of bread proofer or egg incubator. Anything to keep a stable temperature.

If you decide to still make koji outside, put your koji in a pan or pot, with a piece of cloth between the metal and the rice. Close this vessel with cling-film, to avoid any other molds to enter.

It is possible to make your own spores, but I do not recommend it. There is the very real likelihood that in the process you are introducing a mold that produces toxins (many of which are super potent) – and there is no way to know whether or not that is the case. In a home you can’t work cleanly enough to avoid such a contamination.

The spores are meant to be used on any substrate. I have successfully grown koji on meat, but felt a bit unsafe :)

For beginners I recommend to grow the white koji on rice, it is the easiest. If you feel you achieved that, you can try to grow them on barley, etc.. There is an article that explains the differences between the strains.

Kind regards,

Viktor

38. stefano novellino

21 APR 2019 REPLY

stefano novellino

Hi Viktor i just found your site with all those great info you want to share and i am so happy !

thanks a lot !!!

best regards, stefano

39. Håvard

19 MAR 2019 REPLY

Hi Viktor

Could you help me with some advice about how to build a wooden koji tray? I am building a fermentation chamber like the speed rack type in Noma’s Guide to Fermentation, and all I need now is a tray for the koji. I tried finding a perforated sheet tray, but it was not possible to get one at a reasonable price where I live.

Any advice about how to build a woode tray would be greatly appreciated!

1. Viktor

21 MAR 2019 REPLY

Hi Håvard,

best/easiest way to do it is to get a three-layer wood panel (https://www.putzer.com/bilder/produkte/gross/Dreischichtplatte_1.jpg) from a woodshop/hardware store. Here you can buy custom sizes. Then you get a board of solid wood, about 6-10 cm high. You can then cut the lengths (or have it cut for you at the store), to fit the perimeter of your panel. Then just screw the boards and the panel together.

Kind regards,

Viktor

2. Tony

21 AUG 2019 REPLY

I am experienced in making Natto and have got my equipment together to make my first rice Koji.

Does it taste nice just as rice ‘cakes’?

By that I mean, turning several times early, then allowing it to bind together in small cakes.

I will try for the upper temperature range to encourage more sugar production.

Secondly, has any research been done on health benefits of Koji?

1. Viktor

24 AUG 2019 REPLY

Hi Tony,

I don’t know rice cakes, but I can vouch that rice koji tastes absolutely wonderful. It’s mushroomy, fruity, flowery.

I think you could try not turning it at all if you want to achieve tightly bound cakes. Just make sure to not make it thicker than 3-4cm, or else the center will overheat/suffocate.

If you are using higher temperatures your koji will be finished earlier, so keep a close eye on it in the last 30-40 hours. You really want to avoid sporulated koji, as spores makes the koji look unseemly and they impart a bitter taste.

I am sure there is research out there – but I am not in it for health reasons, my approach is culinary :) So I can’t say much about health topics regarding koji.

40. Jan

18 MAR 2019 REPLY

Hi Viktor,

Thanks for all the information here, it’s been very helpfull!

I’ve been growing koji on oats to make amazake. But it has sporulated so much that I cannot use it anymore. I’d like to use it to inoculate a new batch of oats. Is this possible? Can I just mix some of it in there? Or maybe dry it, blend it and then sprinkle it on top?

1. Viktor

19 MAR 2019 REPLY

Hi Jan!

it is possible to do that, but I would advise not to do it. The spores that are sold here are pure, single-species spores.

If you continue to make your own spores from previous batches, you might easily introduce species of mold that are not as benign. I think if you do it once (i.e. to take spores from a batch that was made with pure spores), in all likelihood you’ll probably be fine, but don’t take spores from a batch that you have made from harvested spores already.

41. Laurel Hogan

11 MAR 2019 REPLY

Thanks for the advice. At 40 hours it has a nice coating and it looks pretty ready can I pull it now and call it done? I don’t be home to monitor it so this might be a better option.

1. Viktor

11 MAR 2019 REPLY

Yes, it’s probably better.

42. Laurel

11 MAR 2019 REPLY

I’m a little late in responding but I’ve just discovered koji and I’m currently about 40 hours into a koji ferment of wheat and soy (to make shoyu) unfortunately the temperature spiked overnight and I woke up to a temperature of 45°C I am wondering if this will have ruined my koji. It has not sporulated yet and I stirred and cooked it to 27°C. I’m hoping that I can still use it for the moromi. Any advice?

1. Viktor

11 MAR 2019 REPLY

Hi Laurel,

I think it should be fine for moromi. It’s not ideal of course :) but it should work fine. Make sure to keep a close eye on it. If it starts to get kind of yellow/green or if it starts to “dust”, get it out of your box and make a moromi with it.

43. Cory Hughart

5 MAR 2019 REPLY

I took a class offered by the amazing Jeremy Umansky, and his solution for keeping the humidity at the right mark just blew my mind. Now, he uses a commercial dehydrator to keep the temperature constant, so how does he keep it humid? Plastic wrap! A simple stainless steel tray with plastic wrap covering and 4 holes poked. I had developed a whole temp/humidity system with an Arduino and sensors, but instead I tried his method with a humidity probe inside the tray—and what do you know, perfect 90% humidity! I kinda feel weird giving away this amazing secret, but I don’t think he would mind (I hope).

1. Viktor

5 MAR 2019 REPLY

Hi Cory,

that’s a great tip, thanks a lot! The easiest solutions are often not the most obvious ones! I will definitely put this into the article.

Kind regards,

Viktor

44. Nick

23 JAN 2019 REPLY

Trying to grow Koji on a mix of grains meant for my chickens… I see the spores favor the cracked corn first… Its been over 50 hours and not quite ready to harvest… have you had similar results?

1. Viktor

23 JAN 2019 REPLY

Hi Nick!

Is the Koji meant for the chickens or for you? :D

Generally I find it much, much easier to grow Koji on one thing only at a time. I.e. only on rice, only on barley, etc.

The time it takes depends on the strain. I can’t remember right now which strain it is, but one of them can go on for a long time without starting to sporulate. If you notice that bits and pieces are starting to get yellow/green spots you should stop the Koji right away as it is starting to produce spores, and you don’t want that, they bring a bad side taste.

Kind regards,

Viktor

45. Alexander Henao

14 JAN 2019 REPLY

Hello Viktor, very informative thanks for sharing!

I have setup very similar to yours, just not made of wood. The issue I’m having is regulating the humidity. I have a humidity controller and a humidifier. When I start the process everything works as it should, and when I reach the desired humidity the controller stops power to the device. Problem is when the humidity lowers again, the controller turns on power to the device, but the device does not actually run. I would then have to manually turn on the humidifier every time, defeating the purpose of the controller. Does the model of humidifier you have turn on automatically when power goes on? Any suggestions? or do i just need to buy one that starts when plugged in?

Thanks!

46. Alexander Henao

14 JAN 2019 REPLY

Hello Viktor, very informative thanks for sharing!

I have setup very similar to yours, just not made of wood. The issue I’m having is regulating the humidity. I have a humidity controller and a humidifier. When I start the process everything works as it should, and when I reach the desired humidity the controller stops power to the device. Problem is when the humidity lowers, the controller turns on power to the device, but the device does not actually power on. I would then have to manually turn on the humidifier every time, defeating the purpose of the controller. Does the model of humidifier you have turn on automatically when power goes on? Any suggestions? or do i just need to buy one that starts when plugged in?

Thanks!

1. Viktor

14 JAN 2019 REPLY

Hi Alexander!

I had the same situation once. I sent back the humidifier I bought and went on to look for another one that would turn itself on when it gets electricity. I found that it works with the Medisana humidifier. I am not a huge fan of the thing, but it does work as it should now. I kept my eye open to find a humidifier with a mechanical knob.

2. Will

19 FEB 2020 REPLY

Hi, I know it has been a long time since you posted this, but I get around this problem by tightly taping a coin to the ‘on’ button of my small humidifier.

47. Alejandra

26 NOV 2018 REPLY

Hello Viktor,

I’m very new with this but I have a lot of interest to lean about it. It is posible to grow Koji if I do now have spores, I mean can I create the atmosphere to grow it. For example at the begging of the year I was trying to make vinegar but suddenly I realized that a scoby was growing in my base so I made kombucha.

Kind regards

Ale

1. Viktor Gruber

26 NOV 2018 REPLY

Hi Alejandra,

I suppose you mean to ask if you can make Koji without spores.

You will need the spores, it is the only way to make sure that the mold that is growing is not producing any toxins. Wild molds, like Aspergillus niger for example, produce super toxic compounds. So getting the right spores is the only way to make sure that you get a safe product.

Kind regards,

Viktor

48. Kal

21 NOV 2018 REPLY

Hi Victor,

I am about to build my first ever box for koji, an this page has been incredibly helpful! I was wondering what your newest setup is like, and how it is working out for you.

Thank you!

–Kal

1. Viktor Gruber

22 NOV 2018 REPLY

Hi Kal,

I am quite happy with the new box!

However, there are two things that I am not entirely happy with:

1: when the door gets wet, the wood expands and I can’t close it completely anymore. Not a big deal.

2: The upper rungs are often warmer then the lower ones. This is because after 24h the Koji starts to produce its own heat, which then of course rises up. Maybe a small fan on top would solve this problem.

Kind regards,

Viktor

49. E

29 OCT 2018 REPLY

Hi Victor

Thank you for this information. Once the koji is produced, is it possible to dehydrate the rice for longer storage?

1. Viktor Gruber

29 OCT 2018 REPLY

Hi Ellen,

yes that is possible! But you need to be careful with the temperature. If it is too high, you will destroy the enzymes. So it’s best to dehydrate it at 35-40°C.

The koji rice stays good in the fridge for one week. You can also freeze it, instead of drying it.

Kind regards,

Viktor

1. Hjalti

4 JAN 2019 REPLY

Hi Viktor!

Regarding the temperatures harmful for koji and its useful products, I was wondering:

Koji produces amylase and protease enzymes (A. is useful for breakdown of starches, whereas P. breaks down protein chains).

In beer brewing, amylase from the malted grain is essential for the conversion of starches into sugars and is most active at relatively high temperatures of around 65°C (and therefor I assume doesn‘t denature until somewhere above this temperature). Is koji amylase any different from malt amylase in this regard?

I‘m not sure at which temp protease denatures. Do you have any information on this?

As you note, the koji spores themselves die somewhere above 40°C.

So, do I conclude correctly, that if you are dehydrating koji exclusively for later us as a starch converter (as in sake and amazake), one could do so at higher temperatures (up to approx. 60°C)?

Btw, thx for your really informative website!

1. Viktor Gruber

7 JAN 2019 REPLY

Hi Hjalti!

Sorry for not replying earlier =)

You are right, in beer brewing the temperatures can be quite high. However, if I remember correctly, the mash can be kept at 35°C for the protease phase (which usually done if the mash is destined for yeast propagation. Holding 35°C will result in bad foam stability due to a lack of proteins).

So I am assuming that higher temperatures will denature the proteases. It is for that reason that I recommend a drying temperature of 35-40°C. Probably higher temperatures are possible, but just to be on the safe side it is probably better not to use too high temperatures.

I have not yet found much about the proteases that Koji produces, so I am assuming them to be similar to the ones in malt.

Another interesting thing is that the guys from Noma make their beef garum at 60°C. So, surely, some protein degradation must be happening.

So, I guess you can dehydrate your Koji at 60°C as well, but I think it’s still best to do so at 35-40°C, as the stuff itself isn’t that wet after all. I think the enzymatic potential will be higher/better if you dry it at 35-40°C.

Kind regards,

Viktor

50. marcello panchetti

8 OCT 2018 REPLY

Hello Victor,

Thank you for your articles.

I’m an Italian house miso maker and I do my job with a very primitive sysyem: a bulb lamp into the incubator connected to a thermostat.

What I don’t understand in your article is:

1) what a dehydrator is for?

2) heating the water in the pot you obtain humidity for the environment, but also you obtain the necessary heat for incubating, right?

Thank you

Marcello

1. Viktor Gruber

8 OCT 2018 REPLY

Hi Marcello,

the dehydrator has the same function as your lightbulb, to warm the box. The idea with the warm water was meant to heighten the humidity, but frankly I have soon stopped with this idea. I built a new box, which I am going to describe in this article in a few weeks (hopefully).

Kind regards,

Viktor

51. Shalom Simcha Elbert

28 SEP 2018 REPLY

Hi Viktor!

Thank you for the great articles. I would like to know how the koji after being grown on the rice should be stored? As well, how the spores should be stored and how long they last for.

Do you also have the suggestions how one should try and make miso from soy, barley and chickpeas and what the actual miso would need.

One last question, isn’t tamari the liquid coming out of the miso not soy sauce?

Thank you in advance!

Shalom

1. Viktor

28 SEP 2018 REPLY

Hi Shalom!

The Koji Rice can be stored in the fridge for up to two weeks. You can also freeze it, but it will decrease its potency somewhat.

The spores are viable for at least a year. If they are older than one year, you can just use a bit more than usual and you will still have good results. Mold spores are made by nature to persist for a long time, after all :)

They should be stored slightly below room temperature in a dark and dry place.

I am planning on writing an article on how to make miso soon! You can follow either my facebook or instagram account to get the update once the article is online! :)

When speaking of Tamari, usually the liquid coming out of a miso is meant, but it can also be a type of Shoyu, which is made from soybeans only. The latter is a bit of an artifact of the commercial marketing of soy sauce in the west.

Kind regards,

Viktor

52. Sylvia

15 MAY 2017 REPLY

Hey Viktor!

Danke fuer deinen Beitrag, und ich als Koji-Beginnerin bräuchte vor allem einen Artikel darueber, welches Koji ich fuer welches Projekt verwenden kann.

Ich stehe ein wenig hilflos vor den 6 angebotenen Kojis und weiss nicht, was das Richtige ist.

Daher meine Frage oder Bitte: Schreibst du mal was darueber? Welches Koji fuer was in etwa geeignet ist? Danke – beste Gruesse aus Köln, Sylvia

1. Viktor

16 MAY 2017 REPLY

Hey Sylvia!

Danke für deine Anregung! Ich wurde gestern schon mal zu dem Thema gefragt, also habe ich nun einen Artikel geschrieben in dem die Unterschiede erklärt werden. Ich hoffe er ist hilfreich für dich! :)

Which Koji should I buy?

Liebe Grüße,

Viktor

How to Make Koji – A Step-by-Step Guide for Home Incubation

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Koji is an enchanting fungus that is the secret superpower behind many delicious fermented foods worldwide. It's been used for centuries in different cultures to create products like miso and shoyu.

What exactly is koji and how is it used? Well, the word koji can refer to both the actual mold spores (Aspergillus Oryzae), as well as the final product that you get when you grow koji spores on a substrate. The basic premise is that you inoculate a cooked substrate (rice, barley, and soybeans are some of the most common) with koji spores and incubate for about two days. As koji reproduces, it generates enzymes like proteases and amylases.

The power of these enzymes can then be realized in a second fermentation step by combining the rice koji (or barley koji, soybean koji, etc.) with other ingredients (like soybeans to create miso, for example). In this second fermentation, the proteases and amylases break down carbohydrates and proteins in the fermenting product into their smaller building blocks. These smaller building blocks give the final product a sweeter and/or more umami flavor depending on what you're fermenting and can really do wonders to improve the taste of a meal!

So, if you are looking to make koji at home, you will want to follow these step-by-step procedures to get started.

Where to Buy Koji Spores

How to Make Koji at Home - Incubation Setup

Before you can incubate koji at home, you need to buy your spores and set up an incubation system. If you do not have an incubator ready to go, check out the previous link to learn how to build your own as we did. This will be necessary in order to make koji at home.

Once your incubator is ready to go, your next step is to buy spores.

There are many places to buy koji spores and lots of different types of koji spores available, depending on what final product you want to make. A few to get started include:

- Cultures for Health

- GEM Cultures

- Modernist Pantry

- Fermentation Culture

- Kawshimaya

I have sourced all of my koji spores so far from Cultures for Health and GEM Cultures and they have both worked great (despite GEM Cultures' website looking incredibly dated). The light koji rice spores from GEM Cultures is a great starting point, and we love the tempeh options at Cultures for Health.

Choose Your Koji Substrate

Soaked Koji Rice

In traditional ferments, koji is typically grown on rice, barley, or soybeans. White rice is probably the easiest medium to start with, but koji really likes to grow on almost anything given the right environmental conditions. Once you have the process down you can experiment to your heart's content- we've seen people grow koji on everything from vegetables to popcorn!

The rest of our steps assume that you're growing koji on rice for discussion purposes, but the steps apply to other media as a starting point as well.

Soak Your Rice

First, soak the rice in plenty of cold water for at least a few hours or up to a day. I typically use 1 kg of rice, but read through the rest of our instructions first to determine if that amount of rice will work with your setup. After you've soaked the rice, drain it, rinse it, and let it drain off any excess water for about 30 minutes.

Steam the Rice and Cool

Temperature Control is Important

In general, steaming the rice instead of boiling directly in water works better as it keeps the rice from getting too wet. You can use a rice cooker if you have one. I don't, so my setup involves a large pot with a steamer insert. I wrap the rice tightly in cheesecloth or muslin and then set that into the steamer insert.

In my setup, the rice is usually done in about 50 minutes. If you're used to boiling rice to cook it, steaming definitely gives a different final texture- it should be a little rubbery, but not dry and not wet. You can check that your rice is cooked by using your fingers to try and stretch an individual grain; it should be a little squishy and stretch/elongate a bit.

Inoculate Your Koji

Sanitizing Flour to Disperse Koji Spores

It's often easier to inoculate your rice with koji spores if the spores are dispersed in a larger volume of powder, so most people recommend mixing the spores with flour (AP flour or rice flour are fine). First, you'll need to sterilize the flour. While the rice is cooking, heat up 1/4 c. flour (or whatever amount your koji spore packet indicates) in a skillet over medium-high heat. Stir the flour constantly until it is lightly browned, then remove from the heat and let cool. This should be enough to kill any harmful organisms that could be found on it such that your koji will be the only living organism moving forward.

Once your rice is cooked, spread it out onto a large tray or a large clean tea towel or other non-shedding cloth. You'll need to cool the rice down to 104 °F so that you don't kill the koji spores when you inoculate. Use an instant-read thermometer to double-check the temperature at several points within the rice until you are well below this temperature (or an equivalent temperature as indicated on the spores you purchased).

Koji is a living organism and will be killed if it is heated above a certain temperature range, so cooling your substrate to below this limit is quite important. In future steps, we will use our sous vide to control the temperature of a water bath for incubation as well, as if the temperature is too low, koji will not reproduce. There is a sweet spot temperature range for incubation, and we cannot understate its importance moving forward.

Dispersing Koji Spores on Rice

Now for the fun part! Once you're sure your flour and rice are 104 °F or cooler (as indicated on your spore package), mix 5 g of koji spores with the flour in a small bowl (or use the amount of spores recommended in your specific package insert). Put the flour/koji spore mixture in a fine-mesh strainer and sprinkle half of it over the rice. Mix the rice several times with clean hands or a clean utensil, then sprinkle the rest of the flour/spore mixture on top. Mix again for good measure.

Make sure you don't take too long to do this step as you don't want the rice to cool down too much or dry out. As we said, the temperature is going to be important from now on.

Incubate for Growth

Incubating Rice Koji

Next, you'll need to give your koji spores a warm little environment in which to incubate for about two days. There are lots of ways to do this including using an oven with the light on, an aquarium heater in a cooler, heating pads, seedling heat mats, etc. We've written about our incubation rig before which consists of a sous vide immersion circulator in a large water bath, with the koji rice spread out in hotel pans that float in the water bath.

The important thing is to keep the rice between 80 °F and 95 °F for the entire duration of the incubation (or, once again, an alternative temperature as indicated on your particular spore package). If you're new to koji, I'd also recommend sticking a continuously monitoring temperature probe in the rice like the kind that you'd use for barbecue. That way you can adjust your incubation temperature and setup throughout the two days as needed.

Note that after the first day, the koji will start generating its own heat and you should start keeping a closer eye on the temperature. If your rice starts getting too hot, you can give it several good stirs with clean hands or a clean utensil, or create furrows in the rice bed to dissipate some of the heat, in addition to lowering the temperature in your incubator.

Maintaining the appropriate humidity is another concern. Koji doesn't like being too dry or too wet. Leaving the rice open to the air will likely dry it out too much (unless your air is really humid), but insulating the container too heavily can cause condensation that drips back down on the koji (also not good). We've found that in our sous vide setup, covering the container with a thin tea towel locks in some humidity and keeps water from dripping down into the rice (which happened with the cling wrap in the above photo).

Stopping Incubation

Inoculating Soy Beans for Soy Sauce

Koji is typically done after about 2 days, but start checking on it after about 40 hours. It's hard to describe how to tell when koji is “done”, but in general, if it looks slightly fuzzy and cottony white and smells delicious (sweet, floral, chestnutty) then it is likely done.

If you start to see green or yellow spores, stop it immediately as this means the koji is starting to sporulate. It's ok if there are a few patches of green/yellow but if it's really thick and pervasive then it will change the flavor of your final product to more funky and dank. When incubating soybeans for soy sauce, we noticed them starting to turn green (less visible in the photo above) and used that as our cue to stop. Note that this color change could be gradual or rather fast, so be especially vigilant when checking before going to bed or leaving your house for an extended period.

Store and Use Your Koji

Fermenting Soy Sauce

Once you are finished incubating, spread it out and cool again much like you did with the steamed rice at the start. You can break up clumps with clean hands or a clean utensil. The koji will keep in an airtight container in your fridge for about a week. If you want to keep it longer, you can freeze it or dehydrate it. We typically make large 1 kg batches so we will use about half of it fresh for different projects and then vacuum seal the remainder in small bags and freeze for up to a few months.

We will get into how to use your koji in individual recipes, but for now we hope you have a good idea of the basic process for growing koji on rice. It may seem intimidating at first, but we've actually found koji to be pretty easy to grow. To us, the whole process is mesmerizing and addicting- just wait until you get a whiff of the finished koji and we guarantee you will be hooked, too!

Do you have a favorite process to make koji at home? Comment below to share!