Japanese sake is made from rice, koji (rice mold), and water. It has been produced in Japan for about 2,000 years. The sake making process is very complicated but here, we will introduce you to the basics of sake production.
The following chart of sake production outlines the basic process:
The process in chronological order:
- Rice polishing
Seimai refers to polishing the rice. The percentage of rice remaining after polishing is referred to as the Seimaibuai (rice polishing rate), and it determines the classification of the sake produced.
- Washing, soaking & draining
Wash the rice and soak it in water.
- Steaming the rice
Steam the rice and cool it down. After the rice has been steamed it’s separated into two groups, one will be used to make rice koji (rice mold) and the other will be used to make moromi (mash). A small portion of the total rice (around 6%) is taken to be used to make shubo (yeast starter).
- Rice koji production
Sprinkle rice mold on the steamed rice.
- Making the yeast starter
Mix steamed rice, rice koji and water, then add lactic acid into it. Both the manufacturing dates and the sake that is produced will differ depending on whether lactic acid bacteria (natural) or lactic acid (processed) is added.
- Making mash (moromi)
Mix steamed rice, shubo, rice koji and water.
Ferment the mash for 10 to 26 days.
Squeeze out the fermented mash and divide it into genshu (pure sake) and sake kasu (sake lees). The taste and scent will differ depending on the method used to do this and which portion of the genshu is skimmed out of the tank, as well as the timing of pressing.
- Filtering & Pasteurization
Through filtering, the amber color and unwanted flavor elements of the sake are removed. The sake is then pasteurized in order to stop enzymes from producing alcohol at this point.
- Tank storage
Store sake for 14 to 365 days in a dark place with an average temperature of 15 degrees celsius. Length of storage varies depending on the desired product.
- Adding water
Add water to reduce the alcohol content and fragrance. 15% water is the average amount added, except in the case of genshu, which remains unmodified to maintain purity.
- Pasteurization & Bottling
After this second phase of pasteurization the Sake is bottled and shipped if necessary.