Dekoji (removing the finished koji from the koji room)

Dekoji (出麹, "dekōji") is one of the key steps in sake brewing and the final step of koji making. In this step, the finished koji is taken out of the koji room (koji muro) and cooled, to stop the koji mold cultivated there from continuing to grow. This allows the enzymatic activity of the koji to be properly controlled and keeps it in a condition suited to the next stage of brewing. Koji that has gone through dekoji is added to the shubo (yeast starter) or the fermentation tank, and is then ready for the main fermentation process. Because the quality of the dekoji koji has a major influence on the flavor and character of the sake, the work calls for the skill of experienced brewers.