Japanese sake is made from 5 ingredients, Rice, Water, Koji mold, Yeast and at times, Alcohol is added. If you come across sake that contain additives or any other ingredients that aren't the 5 mentioned previously, they will be not be considered Nihonshu/Japanese sake e.g. Umeshu. Below we give a little more insight on what these ingredients are and their importance in sake making.
Brewers use a rice specific to sake making, i.e. sake rice. The reason behind the use is due the high content of starch found in sake rice, with a pure starch centre within the grain. Starch is important in making sake because the starch within the grain will be converted to sugars which then is fermented to alcohol/sake.
An abundance of high-quality water is a vital aspect of sake brewing. Water is used to wash and steam the rice, for brewing and diluting when producing sake.Therefore, a good source of water is an essential factor when establishing a sake brewery.
Special water with an ideal amount of minerals is needed to produce sake. Water with a good amount of potassium, phosphorus and magnesium is needed. Water with containing large amounts of iron and magnese water is not suitable.Koji Mold
Koji mold (Aspergillus oryzae), is a safe and beneficial variety of mold that has koji-fungal enzymes which break down starch into sugar, turning steamed rice in to koji-rice. When making koji-rice, the brewer sprinkles spores of the koji mold over steamed rice which is then mixed in and nurtured for two days to inoculate and cultivate.
Koji-rice supplies koji-fungal enzymes to help create a yeast starter and is also added to the sake mash.Yeast
Yeast in sake making, has a primary function to convert sugars into alcohol. It secondary function is to affect the aromas of sake. The most commonly used yeast today is cultured yeast. There many types of cultured yeast used in sake making, listed below are the frequently used varieties:
- No. 7: One the most widely used yeast, promotes vigorous fermentation.
- No. 9: Produces a fruity and floral aroma, usually used for Ginjo grade sake
- No. 701: A variation of no. 7, has less bubble during fermentation.
- No. 12: Produces rich and rounded tastes, needs low temperature fermentation.
- AK-1: Produces a floral and fruity, low acidity sake.
Apart from cultured yeasts some brewers also use wild/naturally occurring yeast.Alcohol
There are times where a sake brewers might add a small amount of distilled alcohol (a.k.a. brewers alcohol) to the sake mash. There are a few reasons why they would
1. To create a more dry, sharper palate, or to boost the sake's fragrance.
2. When the brewer is satisfied with his sake mash, he adds the brewers alcohol to immediately stop the fermentation process.
3. For low end sake, such as cooking sake, its more economical.