Sake (nihonshu, 日本酒) is an alcoholic drink made by fermenting mainly rice, rice koji (kome koji, 米麹) and water, and then straining the result. Its legal name is “seishu (清酒)”, and its alcohol content is less than 22%.
Like beer and wine, sake is a brewed drink (jozo-shu, 醸造酒). It belongs to a different production category from drinks made by distillation, such as shochu (焼酎) and whisky.
What may be labeled “nihonshu”
Among seishu, only seishu made in Japan using only rice grown in Japan may be labeled “日本酒 (nihonshu)”. This is also the condition for the geographical indication (GI) “Nihonshu” designated by the government. Products made with rice grown outside Japan, or made outside Japan, are not “nihonshu”.
The names based on ingredients and on how much of the rice has been polished away are listed on the Types of sake page.
Ordering at a shop or restaurant
The Japanese word “酒 (sake)” can refer to alcoholic drinks in general, including beer, wine and whisky. When you order sake at a shop or restaurant in Japan, saying “nihonshu (日本酒)” makes it clear that you mean sake and not another drink.
How it is made
Polished rice is steamed, and koji mold is grown on part of it to make rice koji. The rice koji turns the starch in the rice into sugar, and yeast turns that sugar into alcohol. First, a “shubo (酒母, yeast starter)” is made to start the fermentation. Steamed rice, rice koji and water are then added to it in several stages, and the mixture ferments as “moromi (もろみ, fermenting mash)”. When the moromi has finished fermenting, it is pressed and separated into sake and sake lees (sake kasu, 酒粕). Most sake is then heat-treated before storage. Sake that is not heat-treated is namazake.