3 ideas
The percentage of the rice grain remaining after polishing (seimaibuai) directly drives sake classification, because the outer layers contain proteins and fats that create off-flavors while the starchy core yields cleaner, more refined sake. A 50% polishing ratio (daiginjo) means half the grain was ground away to reach the pure center, demanding more rice, time, and cost than a 70% ratio.
Sake is produced by multiple parallel fermentation, where koji mold converts rice starch into sugar at the same time yeast converts that sugar into alcohol within a single tank. This simultaneous saccharification-and-fermentation lets sake reach alcohol levels (around 20%) higher than any other naturally brewed beverage, distinguishing it structurally from beer, where these steps occur sequentially.
Adding a small amount of distilled alcohol during brewing (honjozo-style) is not a cost-cutting adulteration but a deliberate technique that draws out aromatics and produces a lighter, crisper finish. The pejorative association with added alcohol comes from wartime-era practices of bulking volume, which differs entirely from the precise modern brewer's-alcohol additions used for flavor refinement.