Analysis:

The "koji" in the brewing process refers to the brewing raw materials used for fermentation.

Liquor-making with Qu is a characteristic of our country, and how the ancients used Qu is worth studying. Qu is a saccharifying starter. In ancient times, it was regarded as the starter of fermentation. In ancient times, one of the key steps in brewing was to make koji into this kind of base material first, and the proper use of koji often decided the success or failure of brewing. Because Guqu is naturally inoculated with microorganisms, it is easy to pollute miscellaneous bacteria.

In ancient times, there were two ways to use qu. First, the koji is soaked in water, and after the koji starts (that is, after the enzyme preparation in the koji is dissolved and activated), the koji juice is filtered, and then the rice is put into it to start fermentation, which is called the koji soaking method. The other is to mash koji into fine powder and mix it directly with rice, which may be called "the method of bibimbap at the end of koji". The soaking method may be older than the bibimbap method at the end of koji. The soaking koji-making method is probably transformed from the soaking saccharification and fermentation of tillers (grain buds). Immersion is the most commonly used method in Han Dynasty and even Northern Wei Dynasty, which can be used for reference. > soaking method is widely used to reach this conclusion.

In ancient times, people learned that the water for brewing koji should be treated separately according to different seasons. The water brewed in winter can be directly soaked in distiller's yeast; After spring, when the temperature is high and the water is not clean, it is necessary to boil water. Boiled water cannot be used to make koji directly, and it needs to be cooled before making koji (boiling water will burn microorganisms in koji and inactivate enzymes).

When soaking koji, it should also be noted that the soaking time should be determined according to the season and water temperature. To ensure the effect of dipping.