Wine & Spirit Education Trust (WSET) Level 1 Award in Sake 2025 – 400 Free Practice Questions to Pass the Exam

The ingredient primarily responsible for sake fermentation is yeast. In the sake-making process, yeast plays a crucial role in converting the sugars that are produced from rice starch into alcohol. This fermentation process occurs after the rice has been polished, washed, soaked, steamed, and then mixed with Koji mold (Aspergillus oryzae), which facilitates the conversion of starches to sugars. Once the sugars are available, yeast ferments these sugars, producing alcohol and carbon dioxide.

While rice is the main ingredient in sake production, it is the yeast that is actively involved in the fermentation process itself, making it the correct answer in this context. Water is also an essential component of sake, as it affects the taste and quality of the final product, but it does not directly contribute to fermentation in the same way yeast does. Barley is not used in sake production, as it is primarily associated with the brewing of beer.