Seimai-buai
精米歩合
定義
The rice polishing ratio, expressed as the percentage of the original grain remaining after milling. A seimai-buai of 60% means 40% of the outer grain has been removed. Lower numbers indicate more polishing and generally more refined sake.
詳細解説
Rice polishing is one of the most important steps in sake production. The outer layers of the grain contain proteins, fats, and minerals that can produce harsh or off-flavors during fermentation. By removing these layers, the brewer accesses the pure starch core for cleaner fermentation. Polishing to 50% (daiginjo level) takes 10-12 hours of careful milling to avoid cracking the fragile grain. Some extreme examples polish to 23%, 8%, or even 1%, though diminishing returns in flavor improvement occur below about 35%.