- Rice for kōji; rice for kake; rice for shubo
White rice used as a raw material for brewing is divided into koji mai (that made into koji) and kake-mai (掛米) , which is used directly after steaming. (Mai (米) = rice.) Koji-kin grows better into shinpaku-mai, which is generally easier to handle than eating rice (ippan-mai), so brewers in Nada prefer the former for making koji. Koji accounts for 20 to 23% of all the rice used. Kake-mai is simply steamed rice (mushi-mai) which is cooled before being added directly to the main mash moromi. It represents about 80% of all the rice used, and is generally made mainly with eating rice (ippan-mai) . It is also called mi-mai (味米).
Shubo-mai (酒母米) is the rice used to make the yeast starter (shubo), and accounts for about 7% of all the rice used. Of the rice used for making the starter, about 30% is made into koji, and 70% is kake.
Variations in the quality of rice greatly influence the making of koji, the course of moromi fermentation and final sake quality. So the strain of rice, rice-polishing ratio (sei-mai buai), the percentage of each kind of rice to be used and the handling of these various factors is adjusted according to the type of sake to be produced.