Brewing technology: fermentation types of liquor

The usual fermentation types are atmospheric pressure or pressure, intermittent or semi-continuous and continuous, open or semi-closed and closed fermentation; However, according to the biochemical changes of raw materials and fermentation process, it can be divided into two categories: single fermentation and compound fermentation, and compound fermentation can be divided into single line and parallel. Liquor fermentation includes all the above fermentation types, so its complexity is incomparable to any other liquor.

1, single fermentation

Single fermentation refers to a kind of fermentation that uses sugar raw materials without saccharification. For example, shochu is made from various fruit and sugar by-products.

2. Compound fermentation

Compound fermentation refers to a kind of fermentation that uses starch-containing raw materials (starchy raw materials) and needs amylase saccharification.

(1) Single-row compound fermentation refers to a kind of fermentation in which starchy raw materials are cooked, then saccharifying agents such as distiller's yeast are used to convert starchy sugar into raw moss sugar, and then starter is added for fermentation. For example, using sorghum, corn and potatoes as raw materials to produce liquor through liquid fermentation belongs to this type of fermentation.

(2) Parallel compound fermentation refers to a kind of fermentation in which starch is used as raw material and saccharification and fermentation are carried out at the same time. For example, Daqu and bran koji are solid-state fermented to produce liquor, and Xiaoqu liquor production belongs to this fermentation type. In the production of Xiaoqu liquor, such as the early fermentation stage of Sanhua liquor, the material is solid and mainly saccharified, so people are used to calling it saccharification first; Then add water to continue saccharification and fermentation. But in fact, Xiaoqu itself is both a saccharifying agent and a starter, and the temperature in the early stage of solid-state fermentation is also suitable for the fermentation of fermenting bacteria. Therefore, in general, its whole fermentation process should be called parallel compound fermentation, because it is essentially different from the single-line compound fermentation of liquor fermented by liquid mentioned above.