No need to bleed. But leave air holes and press caps 2-4 times a day during fermentation.

After tanking generally 24~48 hours after the start of the fermentation stage, fermentation will be a large number of bubbles upward, and the grape pomace also upward, the formation of a relatively hard pomace cap.

Because 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.

Pressing the cap: that is, the floating pomace to form 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.

Expanded Information

1, temperature: barrel temperature control during the main fermentation period between 15-30 degrees, barrel temperature to the bottom of the pomace cap temperature shall prevail; the temperature of the low fermentation time is extended, out of the color of the wine is lighter, but the taste and quality of the wine is better. Higher temperatures shorten the time, the color of the wine is better, but the taste and quality is not as good as low-temperature fermentation.

2. Fermentation time: the main fermentation generally lasts 7-10 days, the specific time is determined by the grape variety, the amount of sugar and fermentation temperature. 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's 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, making the wine more astringent.

Baidu Encyclopedia - Homebrewing Wine