Rice polishing ratio

Rice polishing ratio (seimai buai) is a measure that expresses, as a percentage, the proportion of white rice that remains after brown rice is polished. It is calculated by dividing the weight of the white rice after polishing by the weight of the original brown rice and multiplying by 100. For example, a rice polishing ratio of 60% means that the outer 40% of the brown rice has been milled away and the remaining 60% is used as white rice. The lower the rice polishing ratio, the more of the outer layers have been removed and the larger the proportion of polished grain. As a result, the sake produced often has fewer off-flavors and a crisp, clean taste. In general, sake made with a higher ratio (leaving more of the outer layers) may have a rich, distinctive flavor, while sake with a lower ratio is characterized by a refined, clear taste. For this reason, choosing the rice polishing ratio is an important factor in sake brewing. Rice polishing ratio is sometimes divided into "true rice polishing ratio" (shin seimai buai) and "apparent rice polishing ratio" (mikake seimai buai), but in general the single term seimai buai is used for both. Because the quality of the white rice obtained through polishing and the size of the transparent area known as shinpaku affect the quality of the sake, managing the rice polishing ratio is extremely important for sake rice.