What is Koji?

Koji (aspergillus oryzae) is classified as a fungus. Its use as a culinary mold is most often associated with it being grown on both grains and legumes. As Koji feeds and digests the nutrition from these substrates, it produces enzymes that have transformative properties when applied to certain foods. Making koji is the first step to many tasty ferments such as miso, sake, amazake (sweet rice beverage), shio koji (marinade), pickles, and soy sauce


Koji fungus produces enzymes that break down and digest proteins, carbohydrates, fats, and, in return, create amino acids and simple sugars that we register as sweet and delicious umami flavor. This is done by the main enzymes: Protease (which breaks down protein and peptides into amino acids), Amylase (which breaks down carbohydrates and starches), and Lipase (which breaks down fats into fatty acids).