Five crucial elements are involved in brewing sake: water, rice, technical skill, yeast, and land/weather. However, the process remains somewhat mysterious, especially to Western cultures.
Since rice does not contain any sugar, it cannot be fermented as is. It has to first be converted into sugar with the help of enzymes found in a particular mold called koji. It’s from this extremely elaborate and complex process that we get sake.
Explained below are a few important things to know about sake:
The degree of milling is the ratio of the weight of polished white rice to the weight of the brown rice before polishing. For example, if the degree of milling is 70%, then the surface layers of each grain are polished away until 30% of the initial weight has been ground away.
Undesirable ﬂavors can result from the proteins, lipids, and other substances present in the surface layers of rice, and therefore, milling is used to remove these unwanted components.
The koji, or malted rice, determines how a sake will taste. Koji is made by causing koji mold to proliferate on steamed rice. Maintaining the optimal temperature and humidity for the mold to grow requires skill born of years of experience and ﬁnely tuned intuition. The preparation of the koji is considered the most crucial step in brewing sake. Koji mainly acts to convert the starches in the rice to sugars, a process called sacchariﬁcation.
The kobo, or yeast, acts to convert the sugars generated by the oxygen in the koji into alcohol molecules. Also, the fragrance special to ginjo-shu and other premium sakes is mainly created by the action of the yeast, and thus, the role of the kobo plays a very important part in the overall sake production process.
Additions are made to the moromi in three stages
— a ﬁrst stage called hatsuzoe, a second stage called nakazoe, and a ﬁnal stage called tamezoe. This three-part process, unique to sake brewing, helps inhibit the growth of unwanted bacteria while it aids in yeast propagation. It also makes it easier to control the temperature of the moromi.
The naturally occurring amino acids in sake contribute ﬂavor elements such as a mild sweetness, a roundness, a slight tang, or a tongue-teasing bitterness.
Added Alchohol refers to alcohol distilled from starchy or sugary sources. Introducing added alcohol to the moromi, or fermenting mash of rice and malted rice, results in fragrant sake with a crisp finish. The Added Alchohol also inhibits the growth of lactic acid bacteria that can cause sake to deteriorate.
Sake ingredients comprise rice, koji, yeast and added alcohol. All ingredients used in Akashi-Tai products are grown locally and of the highest quality.
The shubo, or moto, as it is also known, is a yeast starter made by adding a carefully selected yeast to plain steamed rice, water, and prepared koji. The purpose of making the shubo is to cultivate as pure a yeast starter as possible for use in the fermentation of the sake. Because the quality of the ﬁnal sake is affected by the quality of the shubo, the preparation of the shubo is considered a fundamental step in brewing sake.
The moromi is made by adding steamed rice, prepared koji, and water to the shubo yeast starter. Sake production is quite unusual among brewing processes worldwide, in that sacchariﬁcation of the starches in the rice and fermentation take place simultaneously. Once the additions are made, the mixture is known as moromi until the pressing step that separates the sake from the sake lees.
The acidity indicates the amount of succinic, lactic, malic, and other acids contained in the sake. These organic acids are an important component in determining the crispness and weight of a sake’s ﬂavor. It is the delicate balance between the acids and the sugars that gives each sake its own flavour profile.
Sake is highly sensitive to the temperature and light conditions under which it is stored. Thus, it is best to keep sake in a dark place at a constant, cool temperature (less than 15ºC). Ideally, the
use of fluorescent lighting in the storage location should be avoided. Sake bottles are generally not capped with corks, so proper maintenance of good sake does not require high humidity. In fact, high humidity can contribute to oxidizing of the bottle caps, and can even encourage mold to grow, thereby causing an unpleasant odor. Sake bottles do not need to be stored on their sides. Rather, it is recommended that sake be stored upright in a refrigerator.
Hyogo Prefecture has been a center for sake production since the Tokugawa Period (1600–1867), partly due to locally grown rice varieties being particularly suited to brewing sake. Growers developed the Yamada Nishiki strain in 1923 as the result of a cross-breeding and improvement process. Beginning in 1936, the Yamada Nishiki strain began to be widely used in making sake. Today it is the most popular variety of rice for sake-brewing, and is used by brewers all across Japan. It is said that even another hundred years of rice development will not produce a strain to beat Yamada Nishiki.
Yamada Nishiki, the ultimate rice for sake production, has the following characteristics:
1.Individual grains are large.
2.The starchy center, or shinpaku, makes up a large proportion of each grain.
3.The strain has low protein and lipid content.
The term shinpaku — the two Japanese characters mean“heart” and “white” — refers to the white color of the starchy center. But although the shinpaku makes up a large proportion of each grain, the starch does not have a dense structure. Rather, the starch molecules are loosely grouped, allowing koji mold spores to easily enter the structure. This in turn helps produce superior koji, or malted rice. The best Yamada Nishiki rice is grown in Tojo Town, Miki City, and the surrounding region located about one hour north of Akashi by car.