What is the role of koji mold in sake fermentation?

Koji mold plays a crucial role in sake fermentation by transforming starches from rice into fermentable sugars. This process is essential because sake production involves the conversion of rice starches into sugars, which can then be fermented by yeast to produce alcohol. The koji mold, specifically the species Aspergillus oryzae, is introduced to steamed rice, where it produces enzymes such as amylase. These enzymes break down the starches into simpler sugars that the yeast can utilize, thereby initiating the fermentation process.

This step is foundational in sake brewing, as without koji mold, the starches present in rice would remain unconverted, and fermentation could not occur. Understanding this function underscores the significance of koji in the entire sake-making process, as it sets the stage for the subsequent alcoholic fermentation that contributes to the final product's characteristics.

While enhancing the flavor profile and filtering the sake are relevant aspects of sake production, they are not directly related to the primary function of koji in starch conversion. Fermenting sugars into alcohol is the role of yeast during fermentation, not koji. Thus, identifying the proper role of koji mold is crucial for understanding the fermentation process of sake.