Gather soybeans, wheat, water, and salt
Soak the soybeans overnight
Cook the soybeans until soft
Roast and crush the wheat
Mix the cooked soybeans with the crushed wheat
Add a starter culture or mold spores
Let the mixture ferment for several days to weeks
Stir in a saltwater brine
Press the fermented mash to extract the liquid
Filter the liquid
Heat the liquid to stop fermentation
Cool and bottle the soy sauce