Fermentation

Fermentation is the process by which microorganisms break down a substrate to obtain energy. In sake brewing, yeast mainly converts sugars into alcohol and carbon dioxide, and this is how the sake is made. Unlike respiration, fermentation does not oxidize the substrate completely, and it is characterized by the production of useful substances such as alcohol and organic acids along the way. This gives sake its distinctive flavor and aroma, resulting in a richly flavored sake. Fermentation is an extremely important step in sake brewing, and the outcome varies greatly depending on factors such as temperature, time, and the type of yeast.