What is the primary function of koji-kin in sake production?

The primary function of koji-kin, which is a mold known scientifically as Aspergillus oryzae, in sake production is to convert starches into sugars. This process is crucial because sake is made from rice, which contains starch that must be broken down into fermentable sugars before fermentation can occur. The koji-kin is introduced to steamed rice, where it reproduces and produces enzymes, specifically amylases. These enzymes break down the starches in the rice into sugars during the koji-making stage.

Once the sugars are available, yeast can then begin the fermentation process, converting these sugars into alcohol and carbon dioxide. Therefore, the role of koji-kin is fundamental as it initiates the transformation necessary for sake production, underscoring its importance within the brewing process.

The other options, while they relate to aspects of sake production, do not accurately describe the primary role of koji-kin. Enhancing flavor, fermenting alcohol, and clarifying the beverage involve different processes and components of sake making.