Question

Gracie squeezed some grapes and kept the juice in a vessel for 5 days at room temperature. On the fifth day she found that the juice tasted sour and appeared frothy. What caused this change?

Answer 1

The changes in the grape juice happened due to the alcoholic fermentation of the grape juice that occurs due to the presence of aerobic bacteria. The presence of yeast is the main reason behind the process of fermentation taking place. The froth is produced due to the presence of the formation of acid and carbon dioxide.