Screening: The grapes are sometimes harvested with leaves and unripe or rotting grapes, especially in bad years, and more serious wineries will

screening before vinification. The best grapes are carefully hand-selected, one by one, at the best chateaux that produce the very best wines.

Destemming: The tannins in the stems are highly astringent and often have a harsh, grassy flavor when not fully ripe, so they must be removed in whole or in part.

Breaking the skins: Since the skins of grapes contain important components such as tannins, red pigments and flavor substances, they must be broken before fermentation, especially in red wines

Squeeze out the flesh of the grapes and let the juice and skins come into contact with each other in order to allow these substances to dissolve into the wine. The breaking of the skins must be done to a moderate degree in order to avoid

releasing oils and bad tannins from the stalks and seeds, which would affect the quality of the wine.

Pressing: All white wines are pressed before fermentation (red wines are pressed after fermentation), sometimes without going through the destemming process

and directly into the press. Special care must be taken not to over-pressurize the juice in order to avoid releasing bitter and stemmy flavors. Traditionally, vertical presses are used

. The air bladder presses have a gentle pressure and give better results.

Demulsification: After pressing, the white grape must is usually mixed with grape chips, sediment and other foreign matter that can easily lead to white wine spoilage, which needs to be removed by sedimentation before fermentation.

The sedimentation process needs to be carried out at low temperatures because the yeasts in the grape must can start alcoholic fermentation at any time. Red wines do not need this procedure as the skin maceration

takes place at the same time as the fermentation.

Alcoholic fermentation: The alcoholic fermentation of the grapes is the most important transition in the winemaking process. The principle can be simplified into the following form: sugar in the grapes + yeast

bacteria = > alcohol (ethanol) + carbon dioxide + heat

usually grapes themselves contain yeast, yeast must be in the 10 ℃ -32 ℃ between the environment in order to function properly, the temperature is too low yeast activity slows down or even stops, the temperature will be too high to kill the yeast so that the alcoholic fermentation is completely suspended. If the temperature is too high, it will kill the yeast and stop the alcohol fermentation completely. Because the fermentation process will make the temperature rise, so the temperature control is very important. About 17 grams of sugar can be fermented into 1% alcohol, so to make a 12% alcohol wine, the sugar concentration in the grape juice should reach 204 grams per liter. In general, the alcoholic fermentation of dry white and red wines continues until all the sugar (less than 2 grams/liter) has been converted into alcohol, while in the case of sweet wines, sulfur dioxide is added to stop the fermentation halfway through, so as to retain some of the sugar in the wine. Alcohol concentration above 15% also stops the yeast from functioning. Vin

Fortifie wines use this principle to add alcohol halfway through the fermentation, stopping the fermentation and preserving the sugar in the wine.

Alcoholic fermentation produces alcohol as well as other by-products:

Glycerin: Containing about 5 to 8 grams per liter in a typical wine, and up to 25 grams per liter in a noble-rotted white wine, glycerin gives the wine a rounded, sweet, and easy-to-sip taste.

Vinegar: This is the most common type of vinegar in the world.

Vinegars: Yeast contains enzymes that produce vinegars, and the fermentation process creates a variety of different vinegars at the same time. Vinegars are one of the main factors in the flavor of grape

wine. Alcohol and acid also produce other vinegars that affect the flavor of the wine.

The necessary production equipment for wine and fruit wine producers

I. Production and processing of raw materials

1. Raw material processing equipment: crusher, press, conveyor pump.

2. Fermentation equipment: temperature-controlled fermentation tank.

3. Wine storage equipment: wine storage tank, transfer pump.

4. Filtration equipment: diatomaceous earth filter, plate and frame filter.

5. Refrigeration equipment: freezers, insulated tanks or quick-freezing machine.

6. Sterilization system: boiler or other heating facilities.

7. sterilization equipment: sterilization equipment or sterilization and filtration equipment.

8. Filling equipment: semi-automatic or automatic bottle washing machine, automatic wine loading machine.

Two, raw wine processing

1. Raw material processing equipment: crusher, press, transfer pump.

2. Fermentation equipment: temperature-controlled fermentation tank.

3. Wine storage equipment: wine storage tank, transfer pump.

4. Coarse filtration equipment, such as diatomaceous earth filter.

Three, processing and filling enterprises

1. Wine storage equipment: wine storage tanks, transfer pumps.

2. Filtration equipment: diatomaceous earth filter, plate and frame filter.

3. Refrigeration equipment: freezers, insulated tanks or quick-freezing machine.

4. Sterilization system: boiler or other heating facilities.

5. sterilization equipment: sterilization equipment or sterilization and filtration equipment.

6. Filling equipment: semi-automatic or automatic bottle washing machine, automatic wine loading machine.