Bonan koji (soft, puffy koji)

Bonan koji (膨軟麹) generally refers to koji that is soft and puffy because of its high moisture content. Koji is made by growing koji mold on grains such as rice or barley, and it plays a very important role in the sake-making process. Bonan koji is often cultivated in particularly humid environments, which increases enzyme activity and contributes to the progress of fermentation. However, excessive moisture can lead to a decline in quality, so careful management is required. In this way, bonan koji is an important element in bringing out the flavor, aroma, and sweetness of sake.