Chapter 16 Section 2 Brewing Chemistry of Ancient Chinese Vinegar and Sauce

After the wine is successfully brewed, it seems that vinegar will be obtained naturally, theoretically.Because the ethanol in wine will be oxidized into acetic acid by the air under the action of microbial acetic acid bacteria, and such bacteria are found in general distiller's yeast, and there are often planktonic vinegar mother spores in the atmosphere.So some people claim that the brewing of grain vinegar and grain wine basically happened at the same time.But in fact it is not so simple, because the biochemical process of ethanol to generate acetic acid under the action of acetic acid bacteria needs a suitable environment, and people may not grasp it immediately; Prompt the ethanol and other components in the wine to produce various aldehydes, ketones, esters and organic acids. Therefore, before summing up quite a lot of experience, even if there is some acetic acid in the wine, the liquid may not It has a mellow and delicious vinegar taste, even bitter, which is not really vinegar, nor will it arouse people's interest and liking, it is just a waste of wine.Some people think that the word "醋" appeared later, and vinegar was called "醯〔xixi〕" in ancient times. Therefore, it is not reliable to judge the appearance of vinegar from the appearance of the word "醯".Because the meaning of the ancient word "醯" is not the same as today's "vinegar". Although there are "醯人" and "醯物" in "Zhou Li", and "Qi 醯" in "The Analects of Confucius Gongye Chang", Zheng Xuan, a scholar of the Han Dynasty, said in the note of "Zhou Li": "醯, Meat juice too." Xu Shen, a native of the Eastern Han Dynasty, said in "Shuowen Jiezi": "Acyl, sour." So "Acyl" in the Zhou and Qin Dynasties can refer to sour meat sauce (and the sour taste in meat sauce may come from acetic acid, It can also come from amino acids, lactic acid, etc.), and it may also refer to various sour foods.Scholars in ancient and modern times generally hold the view that there must have been vinegar in my country during the Han Dynasty, and the original word for "vinegar" today is "酱" at that time.In "Jijiupian" written by Shi You in the Western Han Dynasty, there is a saying "Waterflower salt, soy sauce, vinegar sauce"; in "Simin Yueling" written by Cui Shi in the Eastern Han Dynasty, there is a saying "April 4th can be used as sauce" Yan Shigu, a Tang Dynasty man, said: "醯, vinegar, one thing has two names." Jia Sixie's "Qi Min Yao Shu" clearly pointed out: "醋, vinegar is also today." Therefore, it can be judged that "醯" and "醯" in the Western Han Dynasty "Vinegar" refers specifically to vinegar, that is to say, people at that time had brewed and enjoyed vinegar.

According to the knowledge of modern microbiology and brewing chemistry, most of the whole fermentation process of grain vinegar can be divided into three main steps: (1) Starch undergoes saccharification and liquefaction through the action of grain buds or mucormycetes; (2) Through the action of yeast, sugar is converted into ethanol and carbon dioxide; (3) Ethanol is converted into acetic acid by the action of acetic acid bacteria. But these three steps occur consecutively in the same mash, but alternately.In addition, at the same time as acetic acid fermentation, there are other bacterial enzymes involved, such as oxidizing propanol to generate propionyl acid, oxidizing butanol to generate butyric acid, oxidizing glycerol to generate dihydroxyacetone, oxidizing glucose to generate gluconic acid, and decomposing Proteins are amino acids.And these organic acids can be condensed with alcohols to form mellow esters, which will make the vinegar flavor strong, delicious and delicious.According to the summary of modern vinegar-making process experience, the following conditions must be met for the further fermentation of ethanol to generate acetic acid:

(1) The ethanol concentration in the fermentation broth should not exceed 7%; (2) The optimal temperature for the growth of acetic acid bacteria is 30°C, and the temperature of acetic acid fermentation is preferably controlled at 40°C; (3) The fermented liquid should be in full contact with the air, because acetic acid bacteria are aerobic; (4) There must be some nitrogen and phosphorus in the fermentation broth; (5) Reduce bacteria as much as possible. In ancient times, people lacked scientific understanding of fermentation and relied entirely on experience, so it took a long time to explore from brewing wine to making vinegar, and the taste of early vinegar was not very delicious, so in the Han and Tang Dynasties, food was often used Vinegar is called "bitter wine".

The earliest work to record the method of making vinegar is probably the "Shi Jing" written by Xie Tun of the Han Dynasty, which mentions "the method of making soybean thousand-year-old bitter wine", but the description is too brief, and it is difficult to estimate the level of that method.The early work that recorded the methods of making vinegar in detail is still "Qi Min Yao Shu", in which there are not only many "bitter wine methods", but also many methods of making koji and vinegar.For example, there are 23 kinds of "spiritual vinegar method for rice (sticky sorghum)", "cornet (millet with skin) song making vinegar method", "returning wine vinegar method" and "spiritual vinegar method".The raw materials for making vinegar include grains such as millet, sorghum, glutinous rice, barley, wheat, soybeans, and adzuki beans.All he introduced are the methods of making the best balsamic vinegar.Take the "spiritual vinegar method" as an example, the method is as follows: first make vinegar koji, boil the soybeans and mix them with flour, add water to make a cake, spread it flat, cover it with leaves, and let the bacteria multiply on the cake .After a few days, the spores of the Aspergillus germinate and produce hyphae, and then the mycelia produce a large number of yellow-green spores all over the koji.This kind of yellow koji was called "yellow steaming" in ancient times.On the seventh day of the seventh month of the lunar calendar, three dendrobium (hu, one dendrobium is ten buckets) steamed bran and one dendrobium "yellow steaming" are placed in a clean pottery urn. When the two things come into contact with each other and become warm, Mix them up and add water just to cover them.Keep it warm for two days, squeeze out the clear liquid, and put it in a large urn. After two or three days, the urn body will heat up at this time, and the outer wall of the urn should be poured with cold water to let it cool down.At this time, there will be white foam (called "white rice") on the liquid surface, which should be picked up and discarded in time (otherwise the fermentation liquid will not get sufficient oxygen, hindering the growth of acetic acid bacteria, while anaerobic butyric acid bacteria will If it takes the opportunity to develop, vinegar will not work).After one month, the "divine vinegar" will be ripe and edible.From the description of many vinegar-making methods in "Qi Min Yao Shu", it can be seen that during the Northern Wei Dynasty, Chinese vinegar craftsmen had careful observations on several key links in the vinegar-making process, and strictly controlled the conditions. A series of judgments are also in line with the principles of modern science, indicating that the achievements of vinegar making technology have reached a very high level.For example: First, Jia Shi pointed out in the "moving wine vinegar method" (making vinegar with sour wine): after the seventh day of brewing vinegar, there will be "white clothes" (bacteria film of acetic acid bacteria group) growing. Come out without stirring.After dozens of days, vinegar will be produced.When the "white clothes" sink, the vinegar will be more delicious.It can be seen that he has connected the production of vinegar with the growing "clothes", that is, he has noticed the relationship between the development and aging changes of acetic acid bacteria and acetic acid fermentation, and understood that the growth of "white clothes" is necessary for the production of vinegar. condition.Second, at that time, the difference between "Baiji" and "Baiyi" was distinguished. According to the knowledge of modern microbiology, "Baiji" is a rough membrane yeast formed in the early stage of fermentation, and its formation is not conducive to the growth of acetic acid bacteria. grow.However, Jia Shi has correctly pointed out that the opposite measure should be taken to deal with the "white clothes" - get rid of them as soon as possible.Third, they have realized that it is difficult to make vinegar in very strong wine, so the wine used to make vinegar is generally much weaker than the wine for drinking, or when making vinegar, the amount of input has a great influence on raw materials, grain, The proportion of water is much smaller.Fourth, great attention has been paid to the control of the fermentation temperature. For example, it is pointed out in the "Distiller's Grains Vinegar Method": when making vinegar in summer, it is advisable to rinse the urn with cold water to cool down the temperature; to make vinegar in spring and autumn, the urn should be placed in a warm place. , Wrapped with wheat straw and millet stems or often poured with warm water to increase the temperature.Fifth, although acetic acid bacteria are aerobic, they can still breed under the condition of thinner air, while the phyllodes sphaeroides (Baijiao) which is harmful to vinegar brewing are extremely aerobic, and it is difficult to grow them under the condition of lack of air. Therefore, Jia Sixie’s suggestion is to suppress harmful bacteria by appropriately reducing the ventilation, and adopts the measures of “any size of the urn, but only when it is full”, and seals the mouth of the urn with silk floss.But to prevent excessive lack of air, it is necessary to stir it from time to time and add loose millet bran as a filler.These experiences have been used for reference by later generations. Although "Qi Min Yao Shu" has not explicitly mentioned "aged vinegar", the method of barley vinegar has mentioned that clear vinegar (fresh vinegar that has been removed from the bad) "has to be put in a pot for several years", that is, sealed storage, aging Over the years, this is obviously a more mellow aged vinegar.

In the Eastern Han Dynasty, vinegar was not only eaten, but also began to be used as medicine. It is said that Zhang Zhongjing, a famous doctor in the Eastern Han Dynasty, used "astragalus, peony, and osmanthus" to treat yellow sweat (the name of the disease, edema of the head, face and limbs, sweat sticky clothes yellow like cypress juice, waist pain, and difficulty urinating). Branch Bitter Wine Soup".Tao Hongjing's "Bielu of Famous Doctors" said that vinegar can "eliminate carbuncle, disperse water vapor, and kill evil poison".After the rise of alchemy, bitter wine was quickly used by alchemists. It is said that they used bitter wine and saltpeter to make a solution, which actually dissolved many minerals (turned into water), such as cinnabar, cishi, realgar, etc. It is of course a big exaggeration to say), so it has become the main solvent of "water alchemy".Alchemists also dissolved some minerals into vinegar, calling it "Zuowei Huachi", which is also an indispensable medicine in alchemy.

At the latest in the Sui and Tang dynasties, our country had not only proficiently mastered the use of grain as raw material to make vinegar through the continuous process of direct production of koji and fermentation, but also made vinegar with a variety of raw materials, indicating that extensive attempts have been made, so The variety of vinegar is extremely rich.According to the "Tang Xinxiu Materia Medica" written by Su Jing, in addition to grain vinegar such as rice vinegar, barley vinegar, bran vinegar, koji vinegar, and distilled vinegar, there were also sweet and sour vinegars made of maltose. Fruit vinegar such as jujube as raw material.Of course, the most important one is rice vinegar, and because of its most "sour" taste, it is the only one that can be used as medicine.

Shanxi Mature Vinegar and Zhenjiang Balsamic Vinegar are two famous products of traditional Chinese vinegar, each with its own unique flavor and famous all over the world.The characteristics of Shanxi mature vinegar are sweet but not thick, sour but not strong, fresh but not salty, pungent but not strong.Vinegar koji is made from barley, peas and black beans, using wheat husks, bran, wheat straw, and sorghum stalks as koji beds, and molded at 25°C.When making vinegar, first boil glutinous yellow rice and sorghum into porridge, add 20% of the above vinegar koji, and after more than a month, it will become vinegar mash, then add bran and millet bran, mix well, and place it in the koji room at 35°C After 10 days of fermentation, it will become vinegar grains, so it is moved into a shower tank to drench with vinegar.The new vinegar continues to ferment and concentrate through the processes of sun exposure, dew condensation, and ice removal (put it outdoors in winter, the water in the vinegar freezes and floats on the vinegar, and the ice is removed, the effect is similar to evaporation), and the flavor becomes more and more intense. The better it is, it is eaten after one or two years, so it is called old mature vinegar.This is its traditional method of making. This formula and craft have been basically formed in "Qi Min Yao Shu", so its history can be counted as 1400 years.The characteristics of Zhenjiang vinegar are sour but not astringent, fragrant but slightly sweet, rich in color and delicious in taste, and it is an important seasoning for many famous dishes in the south of the Yangtze River.It is brewed with glutinous rice. The first process is to steam the rice with glutinous rice, saccharify and alcoholize at 30°C, and then add bran and bran in batches for solid-state layered fermentation, so that the fermented product can always be kept in full contact with oxygen. , and gradually expand the reproduction of acetic acid bacteria.The vinegar-drenching process also includes filtering and concentrating to remove impurities, thicken the vinegar, and properly sterilize it. This kind of balsamic vinegar must be sealed and stored for six months before leaving the factory.Zhenjiang Vinegar Factory was built in 1850, so far it has been 140 years.But this glutinous rice vinegar has the same origin as the rice vinegar mentioned by Tao Hongjing, so the ancestor of this type of vinegar is also 1400 years ago.

Chinese soybean paste is made from fermented beans and flour, and has a history of at least two thousand years."Jijiupian", which was written in the Western Han Dynasty, already mentioned "soy sauce", and Yan Shigu, a Tang Dynasty man, commented: "The sauce is made of beans and noodles." The "Minyue Order" all mentioned making sauce, and emphasized that the sauce should be made in time, and should not be delayed until the rainy season. There are 12 kinds of music-making methods in "Qi Min Yao Shu", among which are "yellow clothing" and "yellow steaming", which are used for making sauce and vinegar.They are generally scattered pieces of fragments.The former uses whole grains of wheat, and the latter uses pounded and ground wheat flour.Steamed and spread out on a mat of foil, covered with young grass leaves (similar to reed leaves) until a layer of yellow mold grows.This kind of koji can secrete amylase and protease, which can not only saccharify starch, but also alcoholize. More importantly, it can also hydrolyze the protein in beans into amino acids, which is the main reason for making sauce mellow and special flavor. reason.

Regarding the cultivation of yellow mold and how to exert the activity of the enzymes it secretes, when "Qi Min Yao Shu" was written, there was already quite mature and quite scientific experience.For example, Jia Sixie once pointed out that the cultivation of "yellow clothes" should be in the sixth and seventh lunar months.It is now known that the growth of yellow mold requires higher temperature and humidity.The indicated month (equivalent to July and August in the Gregorian calendar) is the hot summer and rainy season in the middle and lower reaches of the Yellow River, with high temperature and high humidity.Another example is to "soak it in water in an urn to make vinegar" when brewing. The so-called "make vinegar" means to let it ferment to become sour (including acetic acid fermentation and lactic acid fermentation). environment, and "ling vinegar" can inhibit some acid-resistant bacteria.For another example, salt must be added when brewing sauce, which can inhibit the reproduction of many spoilage bacteria and bacteria that are harmful to human health.

The traditional method of making soybean paste in my country is roughly to soak and steam the soybeans first, then mix in about 25% of the "yellow steamed" koji made from wheat flour, mix in 15-20% of concentrated brine, and knead into a dough. Put it in the sun for half a month to two or three months (so it should be in time for the rainy season), or stir it indoors for several months to a year, so under the action of various microorganisms, it becomes a soybean paste with unique fragrance. With soybean paste, soy sauce can be extracted from soybean paste by settling, "basket pumping" (filtering), rinsing or pressing.This kind of eating method had already existed in the Eastern Han Dynasty at the latest. "Qingjiang" is mentioned in "Simin Yueling" is soy sauce. Although "Qi Min Yao Shu" does not mention soy sauce in the chapter "Making Sauce", in the chapter of cooking food, there are "Methods of making Zaoyu (shanshan, meat sauce)", "Methods of making raw meat", "Jiang Qing" (that is, "Qing Jiang") is used in both "Pao Dolphin Method" and "Pao Goose Method".In the Tang Dynasty, soy sauce was widely used as a condiment.Interestingly, soy sauce also entered the medical prescription at that time. Sun Simiao's "Prescriptions of Thousand Gold" treats finger pains by "soaking it with soy sauce and honey warm and hot", and also said, "Craucian carp treats all sores and burns them to ashes. Serve it with sauce."The medical book of the Tang Dynasty, "Waitai Miyao" written by Wang Tao, also used the medical prescription of soy sauce.