Vinegar, also known as 醯(xi), bitter wine, and rice vinegar, originated in the Spring and Autumn Period and the Warring States Period in my country, and has a history of more than 3,000 years. Different regions in my country have different products and climates, which have produced local vinegars with their own characteristics. The properties of vinegar: sour, sweet, and neutral. It enters the stomach and liver meridians. It can help digestion and appetite, disperse blood stasis, stop bleeding, and detoxify. The brewing technique of Gaotai vinegar was first introduced from the Central Plains, and was further enriched and developed locally. It is an important symbol of Gaotai's long history of agricultural culture and prosperous food culture. The brewing process of Gaotai vinegar is as follows: First, boil the touzi. Also called boiled vinegar, the ingredients are prepared according to the ratio of 2.5 kg of highland barley and 5 kg of bran. First, wash the grain, add water and boil it, and let it cool. This is boiled touzi. The pot used to boil vinegar must be a pot for steaming buns, not a pot for boiling meat, and it cannot be contaminated with meat. The second is to make touzi. Also called fermentation, the hot vinegar seed is crushed and mixed according to the above proportions and poured into the vat, stirred into a rice paste, pressed with wheat straw and adobe, and placed in the sun to ferment for 9-11 days. The third is to mix vinegar. Fry two kilograms of highland barley in a pot until it turns brown, then add water to the pot, boil the highland barley, and then pour it into the vat and mix it with the fermented vinegar seed into a porridge-like state. Ferment for about ten days, divide it into components, pour it into a porcelain or clay pot, and expose it to the sun until it is hard. During the drying process, the surface layer must be penetrated. After the vinegar starter is dried, it should be turned over every three to five days, and the surface layer should be patted clean after turning over. The fourth is to pour vinegar. Put the vinegar dregs in pots and vats, and expose them to the sun for 10-20 days. The vinegar dregs will turn black and red. Take about 5 kilograms each time and put them into a pouring basin (use a small vat one meter high, drill a small hole about 3 cm from the bottom of the vat, and insert a small tube into the small hole on the wall of the vat), add water and soak for 8-10 hours, and start pouring vinegar. Every morning, soak the vinegar dregs until noon, pour the vinegar into a basin and dry it; at noon, add water to the vinegar tank and soak it until the afternoon and pour it again. Pour out the vinegar dregs, pat them to light and dry them into koji or feed them to chickens and pigs, and pour the second vinegar into the vinegar dregs for the third time. Repeat the process until the sour taste of the vinegar dregs is completely drained. The fifth is to dry the vinegar. Put the thin vinegar poured in a basin or a tank and expose it to the sun for about half a month. It evaporates and becomes thicker, and the color turns black, which is the mature vinegar. Clean the vinegar every three mornings, and salvage the mosquitoes that fall into the vinegar every day. It is best to use porcelain to clean the vinegar. The sixth is to boil the vinegar. In the mountainous area of Gaotai County, there is a procedure of boiling vinegar. The concentrated mature vinegar after sun exposure is filtered out with a fine sieve or gauze to remove impurities, and then put it into the pot with pepper, chili, mushrooms, dried ginger and other condiments, heat and boil for 23 hours, and filter out the residue to get the finished vinegar. During the entire brewing process, special attention must be paid to environmental hygiene, especially meat and fish. There is a local custom that people try not to eat vinegar that has just been sun-dried, but to eat vinegar that has been stored for the previous year. Vinegar that has just been sun-dried is fresh but has a lighter taste, and the vinegar liquid is clearer (thinner), while aged vinegar is thicker, has a mellow taste, is rich in nutrients, has a shiny black color, and has a strong aroma. The vinegar dregs that have been soaked in koji are placed on clean wheat straw, compacted, polished, and dried, and used as the fermentation koji for the next vinegar brewing. However, the color must be red with a hint of purple. If it is grayish white or black, it is moldy and cannot be used.