Rice polishing (seimai)

Rice polishing (seimai) is the process of milling the surface of brown rice (genmai) to remove some of its components. This step is extremely important in sake brewing. The outer layers of the rice contain large amounts of proteins, lipids, ash, and vitamins, which can have an adverse effect on the sake. Removing them improves the quality and flavor of the finished sake. Rice polishing is also described as "polishing the rice" (kome o migaku). The lower the rice polishing ratio, the whiter the rice becomes and the more its character stands out. For example, a rice polishing ratio of 50% means that 50% of the brown rice has been milled away. In general, the lower the rice polishing ratio, the higher the quality of the sake that is brewed.