Wine & Spirit Education Trust (WSET) Level 3 Award in Sake Practice Exam

In a traditional batch steamer used for making kōji, rice designated for kōji is placed at the top. This positioning is crucial for a few reasons. The steam rises from the bottom of the steamer, and placing the rice at the top allows for even exposure to the steam. This is essential for achieving the right texture and moisture content in the rice, which are pivotal for the successful fermentation process that follows.

Additionally, the rice at the top gets the benefit of the most direct steam heat, which ensures that it cooks properly without becoming overly soggy, thus fostering a conducive environment for the development of the koji mold, Aspergillus oryzae. By layering the rice in this manner, it aids in the precise regulation of cooking time and temperature, leading to optimal koji production, which is crucial for sake brewing.