Classification of distiller's yeast. Looking at the history of brewing with grain raw materials in various countries around the world, we can find that there are two major categories. One is based on the germination of grains, using the enzymes produced during grain germination to saccharify the raw materials themselves into sugar. part, and then use yeast to convert the sugar into alcohol; the other type uses moldy grains to make distiller's yeast, and uses the enzyme preparation contained in the distiller's yeast to saccharify and ferment the grain raw materials into wine. Since the beginning of written records, the vast majority of Chinese wine has been brewed with distiller's yeast, and China's distiller's yeast brewing method has had a great influence on neighboring countries, such as Japan, Vietnam and Thailand. Therefore, before describing the varieties and characteristics of Chinese wine, it is necessary to have a more detailed understanding of Chinese koji. Although the Chinese people have been dealing with Qu Heir for thousands of years and know that distiller’s yeast must be added to make wine, they have never known the essence of Qu Heir. Only modern science has unlocked the mystery. The reason for adding koji to brewing is because there are a large number of microorganisms growing on the koji, as well as enzymes (amylase, glucoamylase and protease, etc.) secreted by the microorganisms. The enzymes have biocatalytic effects and can accelerate the conversion of starch and protein in grains into Sugar, amino acids. The sugar is broken down into ethanol, or alcohol, by the enzymes of yeast. Tillers also contain many of these enzymes, which have a saccharifying effect. The starch in the tillers themselves can be converted into sugar, which is then converted into ethanol under the action of yeast. At the same time, the koji itself contains starch and protein, which are also raw materials for brewing. Jiuqu winemaking is the essence of Chinese winemaking. The main microorganisms growing in distiller's yeast are molds. The utilization of mold is a great invention of the Chinese. Professor Jinichiro Sakaguchi, a famous Japanese microbiologist, believes that this is even comparable to the four great inventions of ancient China. This is obviously inferred from the important position of bioengineering technology in today's science and technology. With the development of the times, the methods created by ancient Chinese people will increasingly play an important role. Types of distiller's yeast The origin of distiller's yeast is unknown. The earliest text about distiller's yeast may be "If you want to make wine wine, you can only use the tillers" in "The Book of Books·Shuo Ming Pian" written by the Zhou Dynasty. Analyzing from scientific principles, distiller's yeast actually evolved from moldy grains. The production technology of distiller's yeast was comprehensively summarized for the first time in the "Essentials of Qi Min" in the Northern Wei Dynasty, and reached an extremely high level in the Song Dynasty. The main manifestations include: complete varieties of distiller’s yeast, perfect technology, and high saccharification and fermentation power of distiller’s yeast, especially southern koji. Modern distiller's yeast is still widely used in the brewing of rice wine, liquor, etc. In terms of production technology, thanks to the mastery of microorganisms and theoretical knowledge of brewing, the development of distiller's yeast has reached a new level. The original distiller's yeast was moldy or sprouted grains. People improved it and made distiller's yeast suitable for brewing. Due to the different raw materials and production methods used, as well as the different natural conditions in the production areas, the varieties of koji are rich and colorful. Roughly during the Song Dynasty, the types and manufacturing techniques of Chinese distiller's yeast were basically finalized. Later generations made some improvements on this basis. The following are the types of Chinese koji: Classification system of koji According to the raw materials for making koji, there are mainly wheat and rice. Therefore, they are called Maiqu and Rice Qu respectively. There are many types of koji made from rice, such as koji made from rice flour, red koji or black rice koji made from steamed rice, and rice koji (Aspergillus oryzae). According to whether the raw materials are matured or not, it can be divided into raw wheat koji and cooked wheat koji. According to the additives in the koji, there are many types. For example, those that add Chinese herbal medicine are called medicinal koji, and those that add legumes are called dou koji (peas, mung beans, etc.). According to the form of music, it can be divided into Daqu (straw bag song, brick song, hanging song), Xiaoqu (cake song) and Sanqu. According to the source of the microorganisms in the koji, it is divided into traditional koji (natural inoculation of microorganisms) and pure koji (such as rice koji inoculated with Aspergillus oryzae, Rhizopus koji inoculated with Rhizopus, and koji inoculated with Aspergillus niger). Classification of distiller’s yeast: In modern times, distiller’s yeast is roughly divided into five categories, which are used in different wines. They are: Maiqu, mainly used in the brewing of rice wine; Xiaoqu, mainly used in the brewing of yellow rice wine and Xiaoqu Baijiu; Red yeast, mainly used in the brewing of red yeast wine (monas wine is a variety of yellow wine); Daqu, used in the brewing of rice wine and Xiaoqu liquor. For the brewing of distilled liquor. Bran koji, which was developed in modern times, uses purebred mold to inoculate a culture with bran as raw material. Can be used to replace some major or minor songs. At present, bran koji method of liquor is one of the main operating methods for liquor production in my country. Its liquor output accounts for more than 70% of the total output. The first song, the second song, the third song, etc. are the names given to different fractions of wine due to the different time of receiving the wine during distillation. That is to say, the naming of the length of fermentation and storage time, such as: Tequ, Chenqu, Touqu, Erqu, etc., is also called quantity and quality grading.
It stipulates that the special song should be stored for three years, the first song should be stored for one year, and the second song should be stored for half a year. Daqu is the general name for liquors that use Daqu as a saccharifying starter, that is, Daqu wine; Tequ refers to special-grade Daqu wine, that is, particularly good Daqu wine.