Hiire (pasteurization)

Hiire (pasteurization) is a step in sake production in which sake is heated to about 60°C to 65°C after pressing (shibori, or joso), in order to sterilize it and halt enzyme activity. The process is important for maintaining quality, as it prevents deterioration during storage. Hiire is a form of pasteurization used in sake. In addition to sterilizing the sake, it helps adjust flavor and aroma and stabilize the character of the sake. Sake that has not undergone hiire is called namazake (unpasteurized), and its taste can differ from that of pasteurized sake. For this reason, hiire is regarded as an essential step for preserving both the shelf life and the flavor of sake. Historically, hiire is said to have been practiced since the Muromachi period in the 14th century, and it continues to be passed down today as a traditional method.