Essential ingredient in washoku

Koji is made by breeding microorganisms such as koji mold on grains including rice, wheat, and soybeans. In order to proliferate, koji mold produces various enzymes which decompose the starch and protein of those rice and wheat into glucose and amino acids. By using those glucose and amino acids, koji mold proliferates.

Koji is used in the production of fermented foods such as sake, miso, vinegar, pickles, soy sauce, shochu, and awamori by utilizing the action of the various types of decomposing enzymes produced by koji mold.