Shio KojiShio koji is a traditional use of koji, the ancient mold that gives us soy sauce, miso, fermented bean paste, and sake. It is made by combining rice koji (cooked rice that has been inoculated with koji spores and then dried), salt, and water and letting the mixture ferment, during which time it develops a sweet, fruity, slightly funky aroma. Shio koji is primarily used as a marinade.