The practice of vinegar is divided into two categories: solid state method and liquid state method. First, the traditional solid state method of brewing vinegar process mainly has 3 kinds: 1, with the big song vinegar: sorghum as the main raw material, the use of big song in the secretion of the enzyme, low-temperature saccharification and alcoholic fermentation, half of the mature vinegar grains placed in smoked grains cylinder, heated with the fire to complete the smoked grains, and then add the other half of mature vinegar grains drenched vinegar soak, and then drenched with the new vinegar. Finally, the new vinegar will be made into vinegar with special aroma by the aging process of sunshine liquid and ice fishing in the winter, which is black quilt in color, thick in texture, and mellow in sour taste. Famous ones are Shanxi old vinegar. 2、Making vinegar with small currant: take glutinous rice and rice as raw materials, first use microorganisms such as root mold and yeast in small currant (also called wine medicine) to carry out solid-state cultivation of fungus on rice grains, and ferment while saccharification. Then, water and wheat curd are added to continue the saccharification and alcoholic fermentation. Then the wine mash is mixed with bran into the solid state into the tank, adding high-quality vinegar grains as seeds, adopting solid-state layered fermentation, and gradually expanding the propagation of acetic acid bacteria. After brewing by aged vinegar, the vinegar juice is poured out by set shower method, added with fried rice color and sugar, clarified, heated and boiled to get balsamic vinegar. The famous one is Zhenjiang fragrant vinegar.3. Take bran as the main material, use glutinous rice with wine or polygonum juice to make vinegar mother for acetic acid fermentation, and the vinegar grains are aged for one year to make bran vinegar with unique flavor. The famous ones are Sichuan Baoning (now Langzhong County) bran vinegar and Sichuan Duxian Sanhui special vinegar. The solid state method of vinegar brewing process, due to the use of nature's wild microorganisms, so the fermentation cycle is long, acetic acid fermentation and the need to turn over the spirits, labor-intensive. At present, it has adopted pure culture of bran as saccharifying agent, added pure culture of yeast made of wine mother, alcoholic fermentation, and then pure culture of acetic acid bacteria made of vinegar mother, acetic acid fermentation and vinegar production. There is also enzyme liquefaction, ventilation and reflux method, after soaking raw materials with water and grinding, first add bacterial α-amylase to heat and liquefy, then add brans to saccharify, saccharify the mash to cool, and add mother of wine to carry out alcoholic fermentation, and when the alcoholic fermentation is finished, after the mash, brans, huller and mother of vinegar are fully mixed, they are sent to the acetic acid fermentation pool with a false bottom, and there is a ventilating hole under the false bottom, which can let the air enter naturally, and make use of natural ventilation and vinegar. The use of natural ventilation and vinegar reflux instead of turning grains, and make the fermentation temperature of vinegar grains uniform until maturity. The output, vinegar rate and labor productivity of enzyme method of liquefaction and ventilation reflux method are higher than that of traditional method. Secondly, there are many kinds of traditional liquid method vinegar brewing process: 1. Take rice as raw material, steam it and then mold it naturally in the wine altar, then add water to make it liquid and ferment it at room temperature for 3-4 months. After the vinegar mash is matured, it is pressed, clarified, disinfected and sterilized, that is to say, it gets the finished product with bright color, fragrant smell, not pungent sourness and mellow taste. Famous ones are Jiang Xi Rose Rice Vinegar. 2、Using glutinous rice, red currant and sesame as raw materials, it adopts the method of adding in stages, undergoes natural liquid fermentation and is aged for 3 years, and finally the finished product is prepared by adding white sugar. Famous ones are Fujian Red Currant Old Vinegar. 3、Acetic acid fermentation is carried out in the quick-brewing tower with filler by using diluted liquor as raw material, such as Dandong white vinegar in Liaoning Province. Liquid fermentation method of vinegar also gradually adopts the new process of deep fermentation. After liquefaction, saccharification and alcoholic fermentation of starchy raw materials, the wine mash is sent into the fermentation tank, access to pure cultivation of acetic acid bacteria expanding level by level, control the temperature and ventilation, accelerate the oxidation of ethanol, generate acetic acid, and shorten the production cycle. Fermenter type is more, now tends to fou use self-priming aerated fermenter. It was firstly used for vinegar production in Federal Germany in the early 50's, called Frings acetic acid fermentation tank, and obtained the patent in 1969. Japan and European countries adopted it successively. China began to use it since 1973.