Homemade soy sauce involves soaking soybeans, mixing them with toasted wheat, and introducing koji mold for fermentation. After fermenting, the mixture is placed in a saltwater brine to age, enhancing its flavor. The final step involves straining the liquid from the solids and pasteurizing it through boiling, resulting in a rich, flavorful soy sauce. This traditional process requires patience but rewards with a uniquely crafted condiment.