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

The koji mold, known scientifically as Aspergillus oryzae, is introduced during the steaming stage of sake brewing. This step follows the washing and soaking of the rice, where the rice is then steamed to create a suitable environment for the mold to grow. The steamed rice is spread out and inoculated with koji spores, allowing the mold to convert the rice's starches into sugars, a crucial part of the sake fermentation process. During this stage, the koji mold establishes itself by breaking down the rice and preparing it for the fermentation that follows, where yeast converts those sugars into alcohol.

The timing and conditions of introducing koji are critical, as it directly impacts the flavor profile and overall quality of the sake produced. The subsequent stages after steaming involve fermentation and shubo preparation, which rely on the successful growth of koji prior to their processes.