Koji claims the culinary spotlight

It is said that the only things new under the sun are those that have been forgotten, and the culinary method of fermenting with koji is, according to Meredith Leigh, currently enjoying just such a renaissance in the West.

A self-described food and farming specialist, Leigh leads workshops at Living Web Farms in Mills River and is the author of the MFK Fisher Award-winning The Ethical Meat Handbook: Complete Home Butchery, Charcuterie, and Cooking for the Conscious Omnivore and Pure Charcuterie: The Craft and Poetry of Curing Meat at Home. She also travels extensively teaching regenerative agriculture and culinary fermentation, and on Saturday, April 27, will host a koji workshop at the Mother Earth News Fair in Asheville with Kirsten Shockey, co-owner of the Oregon company FermentWorks. 

Koji, explains Leigh, is the Japanese name for the mold Aspergillus oryzae, which has “fermentative and enzymatic capacities” that are used to elevate “flavor, texture and processing across many applications in the kitchen.”

The spores are typically inoculated into grains like rice or barley, where enzymes convert the grains to sugar. The inoculated grains are then added to other foods for a secondary fermentation — in Asia, this is the process that’s traditionally used to ferment rice, barley and beans in recipes for miso, sake, soy sauce, tempeh and more.

“Koji is potentially the most exciting thing I’ve worked with in the kitchen,” says Leigh, noting that it was first marketed as a digestive aid. “It represents, in one package, the incredible interplay of the natural world in the kitchen environment.”

Quick cure

Leigh says she’s still learning about koji’s capabilities in living foods and how to best harness them for optimal flavor and texture, but koji-cured charcuterie is an area in which she’s certainly done a lot of experimentation. Pure Charcuterie contains a section on curing meats with koji, and she often teaches classes on this subject.

Curing meat at home is economical, she noted in a 2017 blog post for New Society Publishers, because large quantities of lesser cuts can be processed at home. And it preserves the purity of the meat by eliminating the need for the added sugars and colors typically found in mass-produced charcuterie. 

And curing meat uniquely connects us to the processes of nature. “There is a wonder and a reverence that charcuterie engenders in the home cook,” Leigh wrote. “A respect and a humility at the power of nature and its mechanisms that I have encountered in almost every person I have met who practices any kind of food preservation.” 

Research suggests koji may provide a host of  health benefits, including anti-carcinogenic, anti-allergy, and anti-anxiety properties. But it’s the flavor, as much as anything, that compels chefs such as Patrick O’Cain of Gan Shan Station and Gan Shan West to offer dishes like his tender, koji-aged sirloin that keep diners coming back.

This winter, O’Cain and his chef de cuisine, Will Cisa, cultivated koji for a butternut squash miso, making use of the squash skin and leftover pulp and substituting black-eyed peas for soybeans to give it a Southern spin.

The chefs also like working with the secondary koji ferment shio-koji. Part of shio-koji’s appeal for O’Cain and Cisa lies in its subtlety of flavor in comparison with miso when added to sauces and broths. Shio-koji provides “that savory umami flavor in a vegan, probiotic way,” says O’Cain.

The chefs also use shio-koji as a marinade for meats, both as a seasoning and brining agent, and also as a tenderizer. “Koji has protein-digesting enzymes — proteolytic — that help make meat tender without making it mushy,” he says. “When we had a bavette steak dish on the menu, we would marinate the steaks with [shio-koji] for this effect, allowing us to ‘age’ steaks in a matter of days.”

His and Cisa’s use of koji isn’t confined to the savory: They use amazake (a koji ferment with a sweeter flavor profile) to make a sweet rice porridge, and amazake also serves as the base for a sauce for their pandan leaf cake. “It’s an amazing mold,” says O’Cain. “Powerful stuff in a kitchen.”

For those who want to experiment with koji’s flavor-boosting properties in their home kitchens, Leigh notes that shio-koji and amazake are readily available from online sources and at Asian groceries. Like O’Cain, she suggests using salty shio-koji to brine meat, as well as for producing probiotic quick pickles or “for adding a flavor boost to cooked food, much like a squeeze of lemon at the end of a saute.”

Amazake, or ama-koji, “can be used as a probiotic rice drink, added to sourdough bread starters or as a sugar replacer in some recipes,” she adds.

Japanese tradition

Miso, a salty, umami-bomb paste made from fermented soybeans, is another koji-fermented food that can be made at home — for those who have the time and patience. For those who don’t, there’s a locally made product, Miso Master organic miso.

Marnie Mikell of Great Eastern Sun, parent company of the Rutherford County-based American Miso Co., says the term “koji” can be used to refer to koji spores, which she describes as “the actual culturing agent that inoculates the grain used in making miso” and also to the finished inoculated grain itself.

The company originally started making miso for the American macrobiotic community in 1978 because of its health benefits. “In the mountains north of Tokyo, Takamichi Onozaki, one of the remaining handful of country miso makers of the old school, taught the first [American] miso masters the ancient traditional Japanese way to make miso,” explains Mikell.

To begin the miso-making process, rice is steamed then inoculated with koji spores, which are allowed to grow overnight before being combined with cooked soybeans or other legumes and sea salt. Fermentation times vary from a couple of weeks to years depending on the variety of miso.

Rural Rutherford County was chosen as the site for the American Miso Co.’s production facility because its climate approximates the environment the company’s first miso master learned miso-making in Japan. Traditional miso-making depends on the local climatic environment rather than temperature control.

To learn more about cooking and fermenting with koji, check out Leigh’s workshop with Shockey at the Mother Earth News Fair (see sidebar for details). They will cover primary fermentation techniques for those interested in incubating the mold, and look at sourcing and using secondary ferments in recipes. They’ll also discuss ways of producing shio-koji and amazake in the home kitchen.

WHAT: The Magic of Koji: Preserving Food with Fungus, a workshop with Meredith Leigh and Kirsten Shockey
WHERE: Mother Earth News Fair, WNC Agricultural Center, 761 Boylston Highway, Fletcher. motherearthnewsfair.com
WHEN: The fair runs 9 a.m.-6 p.m. Saturday, April 27, and 9 a.m.-5 p.m. Sunday, April 28. The Magic of Koji workshop happens 11:30 a.m.-12:30 p.m. Saturday, April 27, on the Mother Earth News Stage. The workshop is free with fair admission, which starts at $20 for a day, $25 for the weekend.