Miso soup. Soy sauce. Sake. What do these have in common, besides being staples of Japanese cuisine? The truth is that many foods from Japan hold a key similarity; they contain a fungus called ‘koji’ that is essential in their production and preparation.

Koji is actually a small mold utilized by generations upon generations of Japanese chefs, bartenders, and casual cooks alike. It is just in recent years that American chefs have learned to harness the power of the microbial fungus. Domesticated over 9,000 years ago, koji was found to be alluring in both its scent and its look. A tiny fuzz often found on grain, koji was found by the ancient Japanese to ferment the carbohydrates of its host and create an intoxicating drink we know today as sake. As the knowledge of this phenomenal fungus grew, so did its popularity, and soon many were purposely letting koji grow on other grains. Many other uses were found as time went on, and the fungus made its way to China. In China, koji was used to make fermented bean paste, a popular food both then and now in Chinese cuisine. Fermented bean paste was also made in Japan, but the more popularized term there was ‘miso’. Miso paste was in turn made into miso soup, perhaps the most popular soup in Japanese cuisine. Finally, fermented beans also found use in the production of a popular Japanese condiment. Serving to ferment soy beans to make soy sauce, koji once again found its way into a Japanese mainstay.

In newer cuisines, koji has found many other uses. Modern Japanese restaurants sometimes use koji to enhance the flavor of their steaks, giving them a richer, more unique flavor. A dry-rub, a technique used by many American restaurants specializing in meats, has more recently included koji to intensify the effects of dry-rubbing and then dry-aging. Other chefs have also added it to their cheese, making it more crumbly and flavorful. Koji has found its way to American seafood as well. Some chefs have experimented growing the white fuzz on scallops and cooking them. The scallops, in turn, turn out richer in both aroma and in taste. Finally, koji unami, a popular Japanese dish containing rice, water, salt, and koji that is fermented for at least a week, has been hypothesized to be a great marinade for lighter proteins, such as chicken and fish. Koji is constantly being found to have more uses, especially in Western cuisine.

Who could have guessed that 9,000 years ago, a Japanese farmer found an odd mold on his wheat and decided to harvest it and ferment it because it smelled good? Despite its humble origins, koji has cemented itself as a mainstay of Japanese culture as well as a novel yet effective ingredient in newer, western cuisine. Koji is truly a versatile little fungus.