Moldy Magic

Shared Cultures explores koji in traditional and creative fermented foods

By Rachel Trachten


Eleana Hsu and Kevin Gondo at work growing koji in their Shared Cultures kitchen.


“The mushrooms found me,” says Eleana Hsu, co-founder of Shared Cultures, describing a period when she was depressed at her desk job and hiking a lot to lift her spirits. The extra time out in nature spurred her interest in fungi, specifically koji: a mold fungus used to create fermented foods like soy sauce, miso, and sake. Her partner, Kevin Gondo, shared her interests, and both were fascinated with how microbes can transform one thing into another.

Gondo grew up in Texas, where in 1962, his grandparents opened the first Japanese restaurant in Dallas. Many years later, the young man sensed he had inherited their entrepreneurial spirit as he tried forming a tech startup. That didn’t pan out, but Gondo still longed to start a business. When Hsu left her job just before the pandemic, the couple started Shared Cultures as their own enterprise. It supplements their part-time work for Far West Fungi.

Working out of a shared commercial kitchen in San Francisco, Hsu and Gondo prepare inventive condiments and marinades like Morel Modern Miso, Lion’s Mane Modern Miso, Split Pea “Soy” Sauce, and Walnut “Soy” Sauce—all based on koji. Their umami seasonings can replace salt in many dishes. Both regard using koji as a way to honor their personal cultural traditions while also reimagining them. Gondo, age 30, is Japanese-American. Hsu, also 30, recalls that her Chinese grandma used koji, but that her mother longed to be a “city girl” and didn’t embrace the tradition. Hsu and Gondo are self-taught in the art of fermentation and credit their friend and mentor Jeremy Umansky, coauthor of Koji Alchemy, as well as chef David Chang of Momofuku, for inspiration.

Magical Spores

Koji mold growing on rice.

Koji happens in a two-part process: first, growing the mold onto a substrate, often rice, barley, or soybeans, and then using that moldy substance in a second fermentation to make a diverse set of food products. Aspergillus oryzae (or koji mold) grows naturally on rice or millet in wild areas of Japan and China, where the spores are harvested by hand. Most commercially available spores come from a few producers in Japan, who package them as a powder. Hsu and Gondo dilute the spores with flour, then sprinkle this into the substrate. They use organic heirloom rice from nearby Koda Farms, and they’re also pushing boundaries with new substrates like quinoa and lentils.

How do the spores work their magic? To nourish themselves, they digest the substrate by secreting enzymes, mainly protease and amylase, which turn the proteins and starches into amino acids and sugars, making the foods more bioavailable and creating an appealing umami flavor. This happens over the course of 36 to 40 hours as the mixture is heated to 80–90°F in a humid incubation chamber, such as an oven with the pilot light on, a bread proofer, or even the warm spot atop the refrigerator.

The fermentation varies depending on the desired end product. For miso, the koji rice is mixed with salt and cooked legumes, then packed into a fermentation vessel for eight or more months. Hsu and Gondo have created unique miso products by adding mushrooms or cashews.

For soy sauce (shoyu), the koji is grown on cooked soybeans and toasted wheat instead of rice. The transformed beans or grains are then submerged in a salt brine to ferment for a year or more. At Shared Cultures, a soy-free, gluten-free, and grain-free “soy” sauce is under development using lentils and quinoa.

Expanding the Reach of Koji

To try a Shared Cultures product in a restaurant setting, check out the escargot made with cashew miso, butter, and garlic at Oakland’s Snail Bar. Gondo and Hsu are also making traditional products for the Japanese fine-dining restaurant Nisei in San Francisco and developing partnerships with several other eateries.

Koji is the national fungus of Japan, where it’s been used for thousands of years. It’s been popularized in Western fine dining, and Shared Cultures wants to expand its reach even further. “We want to make koji more accessible than it has been historically,” says Gondo. “We’re trying to bring these powerful flavors to the average consumer.”

Note: This dynamic duo is serving the 2022 Fungus Fair as vendor coordinators. “The fair is volunteer based. We found it important to step up and help out,” says Hsu.


clock clock iconcutlery cutlery iconflag flag iconfolder folder iconinstagram instagram iconpinterest pinterest iconfacebook facebook iconprint print iconsquares squares iconheart heart iconheart solid heart solid icon

Pumpkin Miso Soup

  • Author: Eleana Hsu and Kevin Gondo of Shared Cultures
  • Yield: Serves 4


Eleana Hsu and Kevin Gondo of Shared Cultures like to encourage creativity. They say that any brand or style of miso can add complex umami flavors to many dishes. “We used our cashew miso in this pumpkin miso soup to impart cheesiness.”


Units Scale
  • 1 small sugar pumpkin, quartered, peeled, seeded, and cut into 1-inch cubes
  • 1 tablespoon extra virgin olive oil
  • 1 onion, chopped
  • 4 cloves garlic, minced
  • 4 cups water
  • 1/4 cup (3 ounces) miso
  • Garnishes: extra virgin olive oil, baby kale, chopped hot or sweet peppers, or other items that seem appealing


Heat oil in a soup pot and sauté onion and garlic until golden brown. Add cubed pumpkin, water, and, miso. (Don’t worry if the water does not cover all the pumpkin.) Bring to a boil and reduce heat. Simmer until pumpkin is fork tender, about 30 minutes. Remove from heat and purée with an immersion blender until smooth.

Serve with toasted bread. Swirl in some fresh local olive oil, adding baby kale and chopped peppers as a garnish.


  • Category: Soup

Keywords: Pumpkin Miso Soup


clock clock iconcutlery cutlery iconflag flag iconfolder folder iconinstagram instagram iconpinterest pinterest iconfacebook facebook iconprint print iconsquares squares iconheart heart iconheart solid heart solid icon

Roasted Chanterelles with Ghee, Miso, and Honey

  • Author: Eleana Hsu and Kevin Gondo of Shared Cultures
  • Yield: Serves 2


Units Scale
  • 1/2 pound wild chanterelle mushrooms
  • 1/4 pound carrots
  • 1 1/2 tablespoons miso
  • 2 tablespoons ghee
  • 3 tablespoons hot water
  • 1 tablespoon honey (or to taste)
  • Citrus zest (optional)


Preheat oven to 425°F. Carefully clean chanterelles by brushing off dirt, then slice into halves or quarters depending on size of mushrooms. Slice carrots diagonally into ½-inch-thick oblong medallions.

In a medium bowl, thoroughly combine miso, ghee, and hot water. Add the sliced chanterelles and carrots and mix until they are coated evenly with the miso mixture. Spread chanterelles and carrots over a parchment-lined baking sheet and roast in the preheated oven for about 35 minutes or until the mushrooms and carrots are caramelized and golden brown. 

Serve drizzled with honey to taste and citrus zest as a garnish.

  • Category: Sides

Keywords: Roasted Chanterelles with Ghee, Miso, and Honey