Making your own koji is extremely rewarding. It takes patience and some tending over the 40+ hour fermentation period, but once you witness the the beautiful mold develop, you'll be hooked! This recipe guides you through a basic rice koji but you can grow koji on other grains similarly.
3 cups (525 g) of medium to long grain white rice
2 tablespoons (20 g) of white rice flour (gluten-free option) or all-purpose flour