Seimai ketsugen buai (milling weight loss ratio)

Seimai ketsugen buai (精米欠減歩合) is a measure of the proportion of weight lost when brown rice is milled into polished white rice. Specifically, it expresses, as a percentage, how much the weight of the rice decreases after milling relative to the weight of the brown rice before milling. The figure indicates the share of rice lost through the grinding and scraping involved in the milling process, and in general a lower seimai ketsugen buai is taken to mean that higher-quality polished rice was obtained. The measure is also important in sake production, as it affects purity and flavor, and it is taken into account when selecting sake rice and preparing the brew.