Japanese sake is deeply connected to the Japanese climate, its landscape, and its flora and fauna. It is an alcoholic beverage made from rice, water and helped by microorganisms. As rice is Japan’s most important grain and the country is fortunate enough to be one of few abundant in both water resources and microorganisms, a rich and unique food culture has developed, of which sake is a notable speciality.

  1. Suitable rice for sake brewing

Rice is Japan’s staple food and as such, a wide variety of rices are available in Japan. The rice used for sake is a bit different from the kinds of rice used in cooking.

The rice used in making sake is called “Shuzo Kotekimai,” which is the official designation for rice suited for sake brewing. As of 2012, there are about 100 varieties. This type of rice accounts for about 1% of total rice production in Japan.

The criteria for rice suited for sake brewing

  • Large grain size
    (The weight of cooking rice is below 24g, whereas rice for sake brewing weighs 26 to 28g)
  • Contains shinpaku (the white and opaque part at the center of the rice)
  • Lower levels of lipids and protein
  • High water absorption rate
  • After steaming, it should be hard on the outside and soft on the inside

The most prevalent rices suited for sake brewing (Other rices are used but these are the most popular/well-known):

  • Dewasansan (出羽燦燦)
  • Gokyakumangoku (五百万石)
  • Hattan Nishiki (八反錦)
  • Miyama Nishiki (美山錦)
  • Omachi (雄町)
  • Yamada Nishiki (山田錦)
  1. Suitable water for sake brewing

Sake, in its final stage, is around 80% water. Therefore, water quality greatly affects the quality of the beverage. Water also plays a big role in the sake brewing process; such as washing and soaking rice, creating mash, and adjusting the flavor of the final product.

The criteria for the water suited for sake brewing
Water used for sake production must contain potassium, phosphoric acid, and magnesium. These three elements are necessary to aid the propagation of yeast in shubo (the yeast starter). Thus, almost all sake breweries are located near an abundant supply of good water, be it river, well, or spring.

  1. The main microbes that produce sake’s flavor

The main microbes that affect sake flavor are Koji mold, yeast and lactic acid.

Koji mold
Koji mold is a fungus that induces the saccharification in rice. In other words, the conversion of starch to sugar.

Yeast
The yeast used to make sake belongs to the ‘saccharomyces cerevisiae’ species. This yeast is also used in winemaking and baking.

The best type of yeast to use in sake brewing has been selected over the course of this beverage’s long history.

Lactic acid
Bacteria are used to create lactic acid in Kimoto-kei yeast starter (named after Kimoto, a particular school of sake brewing) by fermenting sugar. As with yeast, there are many different types of lactic acid bacteria, each with different benefits.