“Koji: The Science of a Delicious Mold”
by Cynthia Graber
Cook’s Science, September 25, 2016
I don’t know if you caught my article in the Boston Globe this week (I didn’t know it was going to print until Monday!). I met Rich Shih a few months ago and learned about his miso experiments, and, while I’d previously been obsessed with miso, I then became obsessed with koji.
Obviously my Boston Globe article does go through the basic science of koji, but there’s so much more, and I thought it might be worthy of a longer, science- and experimentation- focused story in ATK.
As I wrote in the piece, we’ve been pressing Aspergillus oryzae, commonly known as koji, into our service for thousands of years. The mold, resembling puffs of clouds, grows on damp grains such as rice, and it releases powerful enzymes as it multiplies, along with an intoxicating savory grapefruity scent. And then that rice-koji mixture helps break down and ferment other foods.
It’s been used by humans for as long as we’ve been unknowingly tricking microbes to help feed us, and it forms the basis of Asian flavors as diverse as miso, sake, and soy sauce. In the ATK story, I’ll be able to go into how this works in much more detail.
Today, chefs in the U.S. are discovering the koji’s ability to transform food and employing it in new, creative ways. They’re making unusual varieties of miso—David Chang of Momofuku fame has made, for instance, pistachio and chickpea miso, among others.
Asian chefs have long used a concoction of koji further fermented in salt water to partially cure fish. Jeremy Umansky, a chef in Cleveland, has been exploring beyond that, developing a technique that allows the koji to grow right on meat, by first coating the meat with rice power and incubating the koji atop it; the enzymes released by the microbe start to break down and cure the meat, producing incredibly tender dry-aged steak in 72 hours as opposed to three months. The same technique even allows Umansky to grow a gluten-free fried-chicken breading, the koji mold serving as the coating when he dunks the chicken-fungi combination directly into the frying pan. I’d love to visit Umansky and learn more in person about his entirely new uses of koji.
I plan to explore the science and experimentation in stories such as these, but there’s more. Scientists at Clark University are studying koji’s domestication; it’s closest relative is toxic, while the one we humans have employed for thousands of years was coaxed out of toxicity and cultivated to supply flavors that we now crave. John Gibbons, whom I mentioned briefly in the Globe, is doing fascinating research trying to tease out how this domestication occurred, and what it can tell us about our relationship with microbes.
I’ll explore the science of how koji works its food magic and the research into its domestication, as well as the history of koji use in Japan and throughout Asia. But the history of koji in America offers another bizarre angle in the story of this captivating microbe. Because this actually isn’t the first time that koji has taken America by storm. The earliest koji sighting in the U.S. appears to be back in the late 1700s, when Samuel Bowen in Georgia makes and sells Chinese soy sauce, which he learned about in China. This is also the first appearance of the soybean in the U.S.
Then in the late 1800s, a Japanese scientist in Chicago named Jokichi Takamine demonstrated that he could make whiskey faster, and more cheaply, by using koji; Adam Rogers wrote about this whiskey tale in his book Proof, and I’ll speak with him for the story. Takamine also took out a patent on an enzyme created by the mold, the first patent in the US for a microbial enzyme. He eventually produced it on a commercial scale, making him—and koji—one of the forerunners of modern biotechnology.
The story will range from ancient communities in Asia to whiskey-making early biotechnologists through to chefs inventing entirely new foods today, all through the tale of one microbe. What do you think?
I know you’re familiar with my work, but I thought I’d state it again here in case you pass this pitch around: I’m an award-winning print and radio reporter. I co-host the internationally acclaimed podcast Gastropod, about the science and history of food, and recent features (print and online) include these pieces in Orion, The New Yorker, PBS NovaNext, and Matter.
Thanks so much,