gracie squeezed some grapes and kept the juice in a vessel for five days at room temperature. on the fifth day she found that the juice tasted sour and appeared frothy. what caused this change?

A. alcohol termination of the grape juice by anaerobic bacteria
B. lactic acid fermentation of the grape juice by anaerobic bacteria
C. alcoholic fermentation of the grape juice by aerobic bacteria

Question

gracie squeezed some grapes and kept the juice in a vessel for five days at room temperature. on the fifth day she found that the juice tasted sour and appeared frothy. what caused this change?

A. alcohol termination of the grape juice by anaerobic bacteria 
B. lactic acid fermentation of the grape juice by anaerobic bacteria 
C. alcoholic fermentation of the grape juice by aerobic bacteria

anonymous · Answer

acid is produced giving the sour taste and CO2 is produced too - hence the froth. Wild yeast in the air will do the job - only a few are needed to start but they keep on growing in the right environment. Some grapes have yeast on them to start fermentation.

anonymous · Answer

I think it is C because the grape juice is natural and that means bacteria can ferment it.

anonymous · Answer

1) lactic acid - the waste products of this are lactic acid and water.
2) alcoholic - the waste products of this are alcohol, carbon dioxide, and water.

anonymous · Answer

for anyone looking for the answer, it is, alcohol fermentation of the grape juice by anaerobic bacteria