Traditionally, the main raw materials for brewing Chinese vinegar include glutinous rice and japonica rice from the south, sorghum and millet from the north, wheat from the Central Plains, and wheat bran from Sichuan and Shaanxi. Nowadays, broken rice, corn, sweet potatoes, dried sweet potatoes, potatoes, and dried potatoes are often used as alternative raw materials. The raw materials first undergo processes such as steaming, gelatinization, liquefaction, and saccharification to convert starch into sugar. Then, yeast is used for fermentation to produce ethanol.
Finally, acetic acid bacteria ferment the ethanol, oxidizing it into acetic acid.
Vinegar brewed from sugary raw materials can use grapes, apples, pears, peaches, persimmons, dates, tomatoes, and other fruits to make various fruit vinegars. Honey and molasses can also be used to make fruit vinegar. The brewing of these fruit vinegars requires only two biochemical steps: ethanol fermentation and acetic acid fermentation.
Vinegar made from ethanol with the addition of acetic acid bacteria undergoes only one biochemical stage: acetic acid fermentation. For example, vinegar can be made using low-proof alcohol or water-diluted edible alcohol as raw materials using a rapid brewing method, which can be completed in just 1 to 3 days.
White vinegar can be made by diluting edible glacial acetic acid with water, and then adding seasonings, spices, colorings, etc., to create a vinegar with a flavor similar to brewed vinegar.
