Wakitsuki Yasumi (self-heating stage of the shubo yeast starter)

Wakitsuki yasumi is a period within the process in which the shubo (yeast starter) begins to surge up and fermentation becomes active. During this period the shubo raises its own temperature with the heat produced by fermentation, so no external warming is needed. The shubo often reaches its peak temperature at this time, and it is an important stage in which fermentation progresses the most. Because wakitsuki yasumi has a major influence on the flavor and quality of the sake, it is a very important point in the brewing process.