1. Traditional extraction fermentation method; 2. Extraction fermentation method; 3. Carbonic maceration method; 4. Rotating fermentation tank method; 5. Continuous fermentation method; 6. Conical bottom tank fermentation method.

1. Extraction fermentation method:

Select red grapes that meet the process requirements, remove the stems and crush them and then send them to the fermentation container. The amount of grapes entering is about 4/5 of the volume. , while adjusting the sulfur dioxide evenly and appropriately. At this time, pectinase can be added, and then artificial yeast can be added. The fermentation temperature should be controlled at 25 degrees and not exceed 30 degrees. Cycle daily or use other methods to keep the peels soaked in juice to prevent "hats" from forming. The fermentation temperature of red wine should not be too high or too low. This is because if the temperature is too high, the aroma will be lost too much, the wine will appear rough, bitter and astringent, and it is easy to be infected with bacteria; if the temperature is too low, the fermentation cycle will be prolonged and the container turnover will be too slow. , affecting equipment utilization. The color is insufficiently impregnated, the wine is thin, and the structure is poor. During the fermentation period, the sugar content, acidity and pH value of the juice should be appropriately adjusted according to product requirements. The adjusted sugar content should not be too large and should not exceed the fermentation alcohol content by 2 degrees. It is best not to add it all at once. After fermentation (test fermentable sugars or taste based on taste), separate the original wine in time. If the separation is too late, the original wine will be bitter and astringent, and may even smell like legumes. The container after the separation of the original wine should not be too full to facilitate post-fermentation of the original wine. , and the amount of sulfur dioxide should be adjusted in time, paying attention that the sulfur dioxide should not be too high to facilitate malolactic fermentation of the original wine. Malolactic fermentation is best to add artificial strains when the alcoholic fermentation is about to end or just after the end. Malolactic fermentation takes about 7 days. The most suitable conditions for malolactic fermentation are PH=3.2, sulfur dioxide about 20PPM, and temperature 25 Spend. Relatively speaking, the acidity of dry red wine that has undergone malolactic fermentation is reduced, and its taste is softer and more delicate, with a vague buttery aroma in the aftertaste, and it can also increase the biological stability of the wine. After the malolactic fermentation is completed, a small test is conducted to determine the amount of gelatin (or bentonite) to be added. However, red wine generally does not use bentonite because bentonite will decolorize. In addition, bentonite will also bring odor. Add gelatin evenly and be careful not to overdo it. When the original wine is clarified, the barrels are changed again. Later, the original wine can be blended and matched according to the requirements of the final product to ensure product quality and maintain consistency. The finished wine can then be clarified, bottled, and stored in the later stage. The main feature of this method is that extraction and fermentation are completed simultaneously.

Traditional extraction and fermentation process:

2. Hot extraction and fermentation:

This method is to ferment whole grapes or broken grapes Heating beforehand, select the temperature according to the purpose to be achieved, keep the grapes at the selected temperature for a period of time, cool the pulp to about 28 degrees, and add artificial yeast for fermentation. This method can adopt either full hot extraction or partial hot extraction. This method can more completely extract pigments and other phenolic substances in the peel, inhibit enzymatic reactions, and reduce the impact of moldy raw materials on the product. The dry red wine produced by the hot extraction method has bright color, rich aroma, harmonious and soft taste, and is more mature than the wine produced by the traditional method. However, the wine produced by this method should not be stored for a long time.

3. Carbonic maceration:

The method of macerating whole grapes in a sealed container filled with CO2 gas and then performing alcoholic fermentation is called carbonic maceration. Its main process flow:

The whole grapes are placed in a closed container with CO2 gas to cause the grapes to undergo anaerobic metabolism. After several days of maceration, the juice is pressed and separated, and then the juice can be separated according to the white wine method. Alcoholic fermentation takes place. The main feature of this method is that alcoholic fermentation takes place without solid matter. The aim is to produce softer, fresher red wines with lower acidity and more aromatic content.

4. Rotating fermentation tank method:

The rotating fermentation tank method is currently a relatively advanced red wine fermentation method. The rotation of the tank can effectively extract the content of grape skins. The tannins and anthocyanidins are contained in the wine. At the same time, due to the closed fermentation, it prevents oxidation, reduces the volatilization of alcohol and aromatic substances, and improves the traditional fermentation process. The main characteristics of this method are bright color, rich and delicate aroma, high dry extract and mellow wine body. Because fermentation is easy to control, the bitterness of the wine is reduced and the storage period is shortened.

5. Continuous fermentation method:

Grape pulp is continuously fed and discharged in the fermentation tank. The main fermentation process is carried out in the continuous fermentation tank. This method is only suitable for Mass production and average product quality.

6. Conical bottom tank fermentation method:

Based on the traditional technology, the structure of the fermentation tank is improved. The fermentation method is similar to the traditional technology, but compared with the traditional technology. It reduces labor intensity and saves manpower. Its products are also significantly improved in appearance, color, aroma, taste, aftertaste and other aspects compared with traditional processes. Its production cost is slightly higher than the traditional method and slightly lower than the rotating tank method.