Koji rice (koji-mai)

Koji rice (koji-mai) is a raw material rice that plays a very important role in sake brewing and is used mainly to make koji. It accounts for roughly 20% of the total rice used, and its quality has a major influence on the character of the sake. Koji rice is generally a high-quality, specialized rice known as sake rice (shuzo kotekimai). By contrast, kake-mai, the rice used mainly for fermentation, may be ordinary table rice. The importance of koji rice stems from the fact that koji aids saccharification and promotes alcoholic fermentation. Because high-quality rice is required, rice with a low rice polishing ratio is often chosen. In this way, koji rice is deeply involved in the flavor and aroma of sake, and sake breweries place great emphasis on its selection and management.