True rice polishing ratio (Shin Seimai Buai)

True rice polishing ratio (shin seimai buai) is an indicator of the actual degree to which the rice used in sake brewing has been polished. Whereas the ordinary rice polishing ratio is calculated from the weight of the polished rice, the true rice polishing ratio is calculated from whole, well-formed grains of brown rice. For this reason, it reflects more accurately the actual proportion of the rice that remains after polishing. The formula is: true rice polishing ratio (%) = (weight in g of 1,000 whole polished rice grains / weight in g of 1,000 whole brown rice grains) × 100. This makes it possible to grasp the true state of polishing. It is an important factor that affects the quality and flavor of the rice in sake brewing.