What is the food source for the yeast in sake fermentation?

The food source for the yeast during sake fermentation is sugars derived from rice. In the production of sake, the starches present in rice are converted into sugars through the action of enzymes produced during the koji mold fermentation. These sugars then serve as the primary energy source for the yeast, allowing it to ferment and produce alcohol.

This process is the core of sake brewing, where the simultaneous saccharification and fermentation occur. As the yeast consumes the sugars, it produces alcohol and carbon dioxide, which are key components of the final sake product. Understanding the role of sugars in this process is essential for appreciating how sake is made and its distinctive flavor profile.