To leave air holes.

The fermentation stage usually starts 24 to 48 hours after the wine has been bottled, after which a lot of bubbles will rise to the surface and the pomace of the grapes will also rise to the surface, forming a hard pomace cap. As the fermentation process also requires a small amount of oxygen and produces more carbon dioxide gas, so do not seal, to leave ventilation holes, in order not to fall into the dust and small insects as the standard can be.

Main Fermentation Stage

1, Temperature: During the main fermentation period, the barrel temperature is controlled between 15-30 degrees Celsius, and the temperature of the barrel is based on the temperature at the bottom of the pomace cap; a low temperature prolongs the fermentation time, and the wine comes out lighter in color, but with a better taste and quality. Higher temperatures will shorten the time, the color of the wine is better, but the taste and quality is not as good as low-temperature fermentation.

2, pressure cap frequency: pressure cap, that is, the floating pomace formation of a thick layer of hard pomace layer pressed into the wine, one can prevent the pomace on the breeding of bacteria, and the second is to strengthen the peel infiltration, generally 2-4 times a day;

3, fermentation time: the main fermentation generally lasts 7-10 days, the specific time by the variety of grapes, the amount of sugar and the fermentation temperature to determine the time of separation. To determine the separation time.

Separation and filtration standards are: after a fermentation period (a large number of bubbles generated) after the amount of bubbles greatly reduced or disappeared, can smell a very strong wine flavor and taste the disappearance of sweetness can be filtered.

It is best not to leave the wine unfiltered for a long time, because too much time will increase the tannins and other substances in the grape skins that affect the taste and make the wine more astringent.

4, wine separation: after the end of the main fermentation, it is necessary to carry out wine filtration and separation, the best before the separation of 12 hours to stop stirring or pressure cap, so that the wine is not so cloudy, the separation of the best use of the siphon tube using the siphon method, which prevents the wine from being cloudy and exposed to too much air caused by oxidation or acetic acid bacteria infected and spoiled.

After separating the wine, the dregs can be filtered through 3-5 layers of gauze or nylon stockings, and gently squeezed by hand. The pressed wine can also be poured into the siphoned wine for secondary fermentation.

Expanded Information

Grapes should be ripe, full, and free of disease, and the darker the color of the skin, the better. Since the skin of the grapes is likely to have pesticide residues, the washing of the grapes is quite important. Generally speaking, it is best not to wash the bought grapes because homemade wine fermentation relies on the wild yeast microorganisms attached to the surface of the grapes for fermentation.

If you want to wash, it's best to rinse the whole bunch, don't scrub them by hand, and don't brush them, and don't sanitize the grapes to make sure that the wild yeasts are viable. Industrial grapes are not washed, many large wineries have their own plantations, is strictly prohibited the use of pesticides and fertilizers, the market grapes if there are pesticides will have spots on the skin surface.

Baidu Encyclopedia - Homemade Wine

Baidu Encyclopedia - Homemade Wine