Wine & Spirit Education Trust (WSET) Level 1 Award in Sake Practice Exam

The process essential in sake brewing that converts starches to sugars is koji-making. During this important step, steamed rice is inoculated with koji mold (Aspergillus oryzae), which produces enzymes capable of breaking down the starches present in the rice into fermentable sugars. These sugars serve as the primary source of alcohol when yeast is introduced in the fermentation stage.

Koji-making is a fundamental part of sake production because without it, the starches in the rice would remain largely unconverted, leading to a lack of the necessary sugars needed for fermentation and the eventual production of alcohol. The careful cultivation and management of the koji mold are crucial for developing not only the sugars but also influencing the flavor and aromatic profile of the final sake product.

Other processes, such as fermentation and polishing, play significant roles in sake brewing as well but are not directly responsible for the conversion of starches to sugars. Filtration occurs later in the process, typically to clarify the sake after fermentation is complete.