How sake is made
In a sake tank, a mold turns starch to sugar while yeast turns sugar to alcohol, all at the same time.
- stations
- 8
- things upstream
- 26
- raw sources
- 14
- steps from the ground
- 6
The short version
Sake is brewed from rice that has been polished to strip off the outer layers. The rice is steamed, and some of it is seeded with koji mold, which turns starch into sugar. Yeast, rice, koji and water are then added to a tank in three steps, so conversion and fermentation run together. The mash is pressed, pasteurized and matured.
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Polish away the husk
Sake rice is milled to remove the outer layers, which carry fat and protein that would cause off-flavors. Only the starchy core stays. A polish of 70% means 30% of each grain has been ground away.
two to three days to polish below half size
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Wash and steam rice
The polished rice is washed, soaked and steamed. Water quality matters throughout, since it makes up most of the finished sake.
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Grow the koji mold
Spores of the fungus Aspergillus oryzae are scattered over part of the steamed rice. In a warm, moist room the mold grows and releases enzymes that cut starch into glucose and maltose.
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Raise a yeast starter
Steamed rice, water, koji and yeast are mixed into a small starter called the shubo. It gives the yeast a head start before it is added to the main tank.
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Add rice in three steps
On the first day the starter goes into the tank with steamed rice, koji and water. A rest day follows, then a second addition on day three and a third on day four. Because the enzymes make sugar as the yeast eats it, sake can reach a higher alcohol content than beer.
about two weeks of fermentation
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Press out the lees
Fermented mash, called moromi, is pressed to separate the clear liquid from the solid rice lees. Cloudy leftover can be sold separately.
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Heat to stabilize
The sake is pasteurized and filtered. Heat kills remaining microbes and stops enzymes from changing it further.
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Mature and bottle
Sake benefits from a period of cold storage before it is diluted with water to a typical strength and bottled. Undiluted sake is 18 to 20% alcohol.
nine to twelve months
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Worth repeating
- The most polished sake on record, Reikyo Crystal 0, has a polishing ratio of 0.85% or less.
- There are at least 123 types of sake rice in Japan.
- Premium sake is about 25% of production, and non-premium sake is 75%.
- Sake is often called rice wine, but its brewing is closer to beer than to wine.
Back to the ground
Follow every input upstream and sake starts as these 14 raw sources.
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Sources
Cite this page: "How sake is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/sake