There are several reasons for the long hair:
One: Because the grape skin is in contact with the air for too long, the bacteria grow too fast, resulting in mold. Treatment: remove the moldy skin, pay attention not to contact with the wine, get clean and stir 1 to 2 times a day, so that the skin to ensure that the moisture can be, only to fermentation.
Two: the grapes are not fermented at all, the sugar is too high and lead to mold, treatment, add live yeast.
Three: may be in the brewing process and oil contact, or containers are not clean and lead to mold, treatment: the removal of mold, do not shake the top layer of wine removal! After the observation of 2 days, did not continue to mold can continue to ferment, if the mold again, then declare the failure of homebrew.
Microbial expert Han Shenghua pointed out that the traditional winemaking are using natural fermentation process. The so-called natural fermentation, that is to say, after the grapes are crushed into the tank, do not artificially add any strains of bacteria, relying on the grapes themselves to carry the natural yeast, spontaneous reproduction in the grape juice, and ultimately fermented into wine. The hairy grapes in the wine are the result of the vigorous metabolism of another kind of bacteria under aerobic conditions, which is often caused by the cork not being tightly capped or too much water when the grapes are put into the bottle.