Among them, only the cooking process is very troublesome and the operation requirements are strict. For example, pour the soaked rice into the retort, steam for 15 ~ 20 minutes after the garden is ventilated, then pour hot water, turn it over several times, then cover it, steam for a few minutes after the garden is ventilated, then pour water, turn it over and steam for the second time. At the same time, it is also required that the cooked rice is hard outside and soft inside, not raw, loose but not paste, thorough but not rotten, uniform and so on. If you don't master that link well, you can't meet the requirements, which may affect the wine yield.
It is much easier to make wine with raw rice. Raw rice need not be washed, soaked or boiled. After purchasing commercially available rice, 6 grams of koji was added to each kilogram of rice, and 3 kilograms of cold water was added for stirring, sealed fermentation and distillation to obtain the finished wine. Therefore, some people jokingly call raw material brewing technology "fool brewing technology".
Five raw materials can be said to have no "technological process". If a technological process is made up, then this technological process is: ingredients (rice+koji+water)-fermentation-distillation-finished wine.
V rice wine is brewed with raw koji, and one kilogram of wine is obtained per kilogram of rice, with 45 ~ 50 degrees, and the taste is the same as that of traditional brewing, even exceeding.
It can be seen that using raw materials to make wine simplifies the process, saves fuel and manpower, reduces labor intensity and operation skills, and improves the yield of wine, thus greatly reducing the production cost. Moreover, due to the simple operation and extensive management of raw material brewing, large-scale and mechanized production can be completely adopted.
Because of the advantages mentioned above, uncooked wine-making is still welcomed by many wineries, especially those small wineries and family winemaking workshops with low culture and lack of wine-making technology. Even if this new technology is not promoted for a long time, the publicity is not strong. For example, at present, thousands of small wineries and family workshops in Guangxi Province are using raw material brewing technology to produce rice wine. Many manufacturers in Jiangxi, Hunan, Zhejiang, Shanghai and other places. Raw material brewing technology is also used.
However, raw material brewing is a science and technology. As a science and technology, it has certain technical specifications and operating rules. Following these laws, the wine yield will be high; If you violate or fail to follow these rules, you will not meet the requirements of wine production. The reason is that the conversion of starch into wine is the result of biochemical reaction and the metabolic product of microorganisms. If the prescribed action conditions are changed, the metabolite is not wine, but another metabolite, such as acetic acid.
Some people don't understand this truth. They regard science as magic and koji as "elixir", thinking that adding some water to uncooked rice and throwing in a little koji will naturally "change" the wine. Once no wine is produced or not much wine is produced, the significance and function of raw material wine-making technology will be denied.
Now I will interview dozens of successful winemakers with raw materials and personal experience, and summarize a few for the reference of manufacturers who have adopted raw materials and those who are interested in raw material winemaking.
We know that the hope and purpose of brewing are nothing more than two:
First, a higher liquor yield can be obtained; Second, the brewed wine can have a more perfect taste. However, the key link to achieve these two goals is the fermentation process. No matter how good the koji is, the saccharifying power and fermenting power are higher; Although the quality of rice is good, it contains more starch; Although the distillation equipment is advanced, the wine receiving technology is clever. If the fermentation is not well mastered, the yield of finished wine will not be high.
How to ferment and how to manage, general wineries and brewing workshops have certain experience. But there are still differences between raw material brewing and traditional fuel brewing. In the fermentation period, we should pay special attention to and master three links: temperature, anaerobic and fermentation period.
1. temperature (refers to room temperature℃). The fermentation temperature of uncooked liquor should be controlled above 20℃ and below 40℃. When the temperature is higher than 40℃, it is easy to produce acid and even the yeast dies. When the temperature is lower than 20℃, the raw meal is difficult to ferment. The optimum fermentation temperature is 25℃ ~ 30℃.
The relationship between temperature and fermentation period is as follows: high temperature and short fermentation period; Low temperature and long fermentation period. Specifically, when the temperature is 20 ~ 25℃, the fermentation period is 15 ~ 20 days, and when the temperature is 25 ~ 30℃, the fermentation period is about 10 ~ 12 days. When the temperature is 30 ~ 40℃, the fermentation period is usually about 8 days.
The koji is resistant to high temperature, and the yeast can continue to grow and reproduce at 35 ~ 40℃ without producing acid. Therefore, raw materials are used to make wine. There is no "safe summer" problem.
However, there is also the problem of how to spend the winter safely. Practice has proved that it is difficult to ferment raw materials when the temperature is lower than 20℃. If the temperature is lower than 10℃, the fermentation will stop. At this time, the yeast is in hibernation and does not reproduce or grow. Therefore, when the room temperature is lower than 20℃, measures should be taken to keep the temperature above 20℃, so that the raw material fermentation can be carried out normally.
When the room temperature is lower than 20℃, clinker fermentation can be used in addition to heat preservation and temperature rise measures. The clinker fermentation mentioned here is very different from the traditional cooking. The clinker fermentation mentioned here refers to steaming the aniseed casually. The specific operation is to add three times of cold water to raw rice and then cook it with fire. When the rice is basically cooked and cooled to below 36℃, add koji, stir and seal for fermentation. Using this clinker fermentation method, the fermentation is completed in about five days, and then the finished wine is obtained by distillation. In addition, rice can also be cooked directly into rice without making sandwiches.
Second, anaerobic. The so-called anaerobic means that raw rice or cooked rice is put into a fermentation container filled with distiller's yeast and water and sealed, so that it can be fermented without or without air. Especially in the middle and late stage of fermentation, special attention should be paid to anaerobic fermentation. Because in the process of alcohol fermentation, free oxygen is not needed. If there is oxygen in the fermentation process, yeast can get energy through aerobic respiration, completely decompose sugar into carbon dioxide and water, and at the same time produce a large number of bacteria, which greatly reduces the output of alcohol.
Its principle is: fermentation under aerobic conditions, its product is acetic acid, fermentation under anaerobic conditions, its product is alcohol. Therefore, if you don't want acetic acid, you must ferment it under anaerobic conditions.
How to carry out anaerobic fermentation? The practical experience of many wineries is that semi-sealing is adopted in the initial stage of fermentation. The so-called initial stage of fermentation refers to the time from the time when raw materials are put into the fermentation container to the time when millet foam emerges from the fermentation surface. Fully sealed fermentation is absolutely adopted in the middle and late stage of fermentation. The so-called middle and late stage refers to the period from the appearance of millet flower foam on the fermentation surface to the complete end of the whole fermentation.
On the contrary, some manufacturers pay attention to sealing in the early stage of fermentation, but don't pay attention to it in the middle and late stage of fermentation. When the raw materials were put into the fermentation container, they attached great importance to sealing, but no one has seen them since then. Carbon dioxide burst the plastic film, loosened the tied rope, and no one checked and replaced it, so that a large number of miscellaneous bacteria in the air entered the fermentation container, and acetic acid bacteria grew and multiplied in large numbers, even taking alcohol as food. This is why some manufacturers report that the alcohol rate is not high.
Third, the fermentation period. Fermentation period refers to the period from feeding to distillation.
As mentioned above, the fermentation cycle depends on the temperature. High temperature and short fermentation period; Low temperature and long fermentation period. We can't say that the shorter the fermentation period, the better. Of course, we cannot say that the longer the fermentation period, the better. How to properly master the length of this fermentation cycle is an important link to improve the yield of wine and increase the taste of finished wine.
The suitable fermentation period depends on whether the raw materials are completely fermented, and the fermentation period should be extended for one or two days after the raw materials are completely fermented, which is beneficial to esterification and aroma enhancement.
The symbol of complete fermentation of raw materials is that raw starch has been completely converted into sugar and sugar has been completely converted into alcohol. By detecting the contents of residual starch and total residual sugar, it can be judged whether the raw materials are completely fermented. When the content of residual starch and residual total sugar is lower than 1%, it means that the raw materials have been completely fermented.
Some small wineries and brewing workshops have no testing equipment, so how can we know whether the raw materials are completely fermented? The author introduced the methods of seeing with eyes, hearing with ears, tasting with mouth and touching with hands in the book "Raw Material Brewing Technology and its Operation Method" edited by 1996. Due to space reasons, I won't go into details. Here is only a simple way to see and touch, for reference.
Touching by hand means squeezing the fermenting rice grains with the mother's fingers and forefinger. If there is no hardness and roughness, it will melt as soon as it is squeezed, indicating that the raw materials have been basically completely fermented.
Use your eyes to see the raw materials and the colors.
When all or most of the rice floating on the surface of the fermentation liquid sinks into the bottom of the pool, the fermentation liquid turns from turbid to blue, the whole fermentation liquid is in a static state, no longer bubbling, and the rice grains no longer move up and down, which means that the whole fermentation process has been completed and the raw materials have been completely fermented.
Looking at the color means looking at the color change of the fermentation broth. From feeding to bubbling, the fermentation broth is clear and transparent. During the period from the beginning to the end of fermentation, the fermentation broth changed from clear and transparent to rice soup color. From the end of fermentation to esterification, the fermentation broth changed from rice soup to light brown.
Practice has proved that a longer fermentation time is an important measure to improve the yield of wine and increase the aroma of finished wine.
How long will the extension take? The author thinks that it is appropriate to extend the fermentation broth for another day or two when the fermentation broth turns from turbid to clear and the whole fermentation broth is in a static state. From the color point of view, when the fermentation broth changes from turbid to clear and from clear to dull light brown, it can be distilled.
Why extend the fermentation time for a day or two? Because the aromatic substance of wine is protein in raw materials, it is decomposed into amino acids, and then it becomes an aromatic substance through biochemical reaction. This biochemical reaction process takes time, and this time is esterification time.