Question

grapes hanging on the plant do not ferment but after being plucked from the plant can be permitted under what conditions do these grapes ferment is it a chemical or physical change​

Answer 1

It is a chemical change as after fermenting we cannot get the grapes back. For fermentation they require some warmth and anaerobic respiration occurs(by yeast). For anaerobic respiration, air(oxygen) has to be excluded from coming in, and is thus kept in a tightly closed container.