A question about fermentation, what happens to grape pressings?

Question

that go the opposite direction and DO NOT become wine.

Let me rephrase: grape juice left to itself will turn to vineger?
yes/no or does it stagnate

Answer 1

grape juice left to itself will not turn to vinegar. in order for vinegar to be made a substance called "mycoderma aceti" sometimes called "mother'. It causes fementation in wine & cider and turns them into vinegar. Once the vinegar is made, you can transfer the mother to a new batch of wine or cider right away and begin the process all over again

Answer 2

A vintner doesn't let that happen. The grapes are fed through a crusher and yeast is added. This mixture sits in a primary fermentation vat with the skins/etc and allowed to ferment. When the liquid has taken on enough color from the skins, the mixture is pressed. The liquid is retained and put in kegs to ferment/age. The skins are discarded.

Adding the yeast doesn't allow the "nasties" to mess up a batch of wine by ensuring the proper yeast is present.

Answer 3

It depends on the winery. Red wines are fermented with the skins to extract the tannins and color. After the primary fermentation, the wine is siphoned from the skins and solids and continue to ferment in a secondary container. The remaining solids of pulp, skins, seeds, etc. (called pomace) are either dried and used as fertilizer or mulch (the drying removes all the water *and* residual alcohol) or oil can be extracted from the seeds.
More frequently now, the pomace is set aside and distilled to produce grappa. Brandy is distilled wine, but grappa is essentially the discards of the wine that is distilled. It's becoming an increasingly popular spirit in recent years.

Answer 4

No , leave it long enough it will turn to wine