日本酒を語る

Talk about sake

2020.08.05

Knowledge

Machine Supporting Sake〜Work of Rice Polishing Machine

When fall comes, the first thing sake brewery workers work on is rice polishing. For table rice, protein and lipids are providers of umami, but for sake brewing they create undesirable odd flavor. When there is something that does not meet the desired quality, then the undesirable part, mostly contained in the outer portion of the rice, is ground away by a millstone, and this process is done by rice polishing machines. When polishing rice which is used for koji rice, the necessary starch and shinpaku, a core which looks white because of the slightly crude starch, should remain. Rice polishing is to polish rice carefully, as the word indicates. Even the rice is polished at a high speed at first, as the machine gets close to the core part later, it takes time to move and grinds away unnecessary parts slowly and carefully, or otherwise the rice will be broken. Friction also generates heat. Workers compare actual brown rice with the data, confirm the quality of rice of the year, and set the rotation speed and resistance (friction) of the machine according to the polishing rate for the sake to brew. Though the quality of polishing depends on the quality of rice (=brown rice) in terms of protein and lipids, placement of starch, shinpaku manifestation, size of rice grains, and amount of water, they say polishing machine manufacturers are working hard to develop the polishing process so that they can solve problems that result from raw materials. All the people involved in sake brewing say the same thing: “Processing of raw materials is most important. Polishing machines can polish rice, but it requires skills and not every worker can control the machines.” So what matters is performance of machines and workers’ skills to control them. (Cooperated by and photos of polished rice provided by and taken at : Shin Nakano Kogyo Co, Ltd. (Okayama), Dewazakura Sake Brewery Co. Ltd. ( Yamagata))