Sake Brewing Process
Sake is a brewed product which undergoes a relatively complex fermentation process. Since the main ingredients of sake, rice and water, do not have the sugars needed for fermentation, a special malt-like agent (koji in Japanese) is necessary. Koji, known officially as Aspergillus oryzae, is a type of mold produced from rice which turns the starch into sugar by an enzyme process. The koji is inoculated into steamed rice and after about 3 days, is added to the main mixture of rice and water. Yeast is later added to the mixture to convert the sugar made by the koji into alcohol. At the end of fermentation, which typically takes about 28 days from start to finish, the alcoholic content can be as high as 19%. Water is then added to the brew to bring the alcoholic content down to approximately 13-16%, the most common level for most sakes.
Key Elements for an Excellent Sake Brew
| Water: Most people think firstly of rice when they think about sake. However, percentage-wise, water is the ingredient of the greatest amount. Sake breweries have traditionally been located in places where the water is exceptional. Hokkan Sake Brewing takes pride in the local, mildly soft underground water of the Tochigi area. Low in iron and containing an appropriate mineral content, this water is perfectly suitable for brewing excellent sake. Water is used both during the fermentation process as well as in the final water addition. In this stage, the natural alcoholic content of the brew, which is typically 17-19%, is brought down to 13-16% which is generally the most preferred taste. |  |
| Rice: Although sake may theoretically be made from any kind of rice, the very best sakes are made from japonica short grain rice. This rice is rich in the starch necessary for fermentation. Unlike long-grain rice which is relatively hard and thin, japonica short grain rice has a relatively soft and thick center which greatly aids the fermentation process. We at Hokkan use the finest Japanese produced rice varieties, such as Yamadanishiki, Gohyakumangoku, Tochigisake 14, Miyamanishiki, and Hanafubuki which have been specially developed for sake brewing. |  |
| Koji: In the olden days, making koji was the most difficult step in the sake brewing process. Koji today actually refers to two things: 1) Aspergillus oryzae, the malt-like substance needed for transformation of rice starch into sugar and 2) the steamed rice that has been inoculated with Aspergillus oryzae. In days past, rice was left to mold in natural but unpredictable conditions which became the "koji rice." Because temperature and humidity were difficult to control, the quality of the koji rice and resulting final brew were not consistent. Today, however, koji mold can be produced in a powder-like form which is dispersed over steamed rice in a closely controlled sauna-like environment. After approximately 3 days after inoculation, the koji rice preparation is complete and is ready for addition to the main mash. |  |
| Yeast: Yeast is perhaps the most important key for both determining the final alcoholic content of the fermentation as well as determining the taste and flavor of the brew. The stronger the yeast is, the higher the alcoholic content becomes. We at Hokkan carefully select the yeasts we use depending upon the fragrance and taste of the sake we wish to create. |  |