Jeremy Umansky shares how to make the most of mold in ‘Koji Alchemy’

Jeremy Umansky, co-owner and chef behind Ohio City’s Larder Delicatessen & Bakery, released his first book, “Koji Alchemy: Rediscovering the Magic of Mold-Based Fermentation,” on May 6 with co-author Rich Shih, a leading culinary explorer of koji and miso.

Umansky says he hopes the book, which includes a foreword by American food writer and DIY food activist Sandor Ellix Katz, helps brings koji mold to the forefront of culinary conversations. Koji, which is used in many fermenting practices, is the microbe behind the umami flavor of products like soy sauce, miso and mirin.

“This is an ingredient that I would place a lot of money (on) that every American has in their house,” Umansky notes. “We have soy sauce packets from takeout – so it’s something that is there, but we don’t know how it is made. This closes a lot of those loops. As an extension from that too, it is really fun and fulfilling for me to see other people fall in love with a mold the way I have.”

Umansky says he was compelled to write about koji in a way the general public will understand, as much information available is either hyper-scientific or in Japanese. He says “Koji Alchemy” is “the first single-subject book in English completely devoted to it.”

“In my research, I could only find stuff in Japanese or scientific literature, so unless you’re one of the two, it’s really hard to understand,” he explains. “So, seeing that problem, I was wondering where the information was. It really is about the accessibility of the topic.”

“Koji Alchemy: Rediscovering the Magic of Mold-Based Fermentation” is for sale at, as well as at other book sellers.

Leave a Reply