Polishing rice Rice contains albumins, lipids, and minerals in addition to starch. By polishing rice, the amounts of undesirable components are reduced, in proportion to the extent of polishing. The elimination of undesirable components enables the brewer to get more fine sake without undesirable odors and tastes. The heart of the rice polishing machine is a rotating grindstone, much like a grinder for sharpening tools. This grindstone can grind rice to any required size.
Albumin is a component of the cell wall and is distributed throughout the rice.
Other components such as lipids and minerals are primarily concentrated in the outer layers. Therefore, grinding obviously decreases the amount of undesirable lipids and albumin. This process is so delicate that it is impossible to see whether the rice is broken into pieces. Overnight monitoring is necessary. Of course, the cost of very fine sake also increases in proportion to the polishing.