(1) In the process of grape wine-making, the microorganism that plays a role is yeast; The products of anaerobic respiration are alcohol and carbon dioxide.

(2) Alcohol fermentation should be carried out in an oxygen-free environment, so both the air inlet and the air outlet should be closed, and the air outlet should be opened at regular intervals to discharge the generated carbon dioxide.

(3) Student A did not clamp the aeration pipe of the fermentation bottle, and the ethanol produced by yeast respiration was oxidized into acetic acid, and the fermentation liquid flowed out of the aeration pipe and turned sour; Student c mistakenly thought that there was too much fermentation broth in the bottle, which flooded the nozzle of the exhaust pipe in the bottle and made the fermentation broth flow out of the exhaust pipe. Ethanol in A is oxidized to acetic acid, and ethanol can be produced in B and C, so the actual fermentation products of A, B and C are fruit vinegar, fruit wine and fruit wine in turn.

(4) In the process of brewing, yeast produces alcohol and carbon dioxide through anaerobic respiration, and the second student broke the cork because the air pressure in the fermentation bottle was too high to exhaust in time.

So the answer is:

(1) yeast

(2) Glucose, ethanol and carbon dioxide

(3) The fermentation liquid which is not clamped in the gas filling pipe of the fermentation bottle flows out from the gas filling pipe, and the fermentation liquid turns sour.

Too much fermentation broth in the bottle flooded the nozzle of the exhaust pipe in the bottle.

When exhausting, the fermentation liquid flows out of the exhaust pipe.

Grape vinegar (or fruit vinegar) wine (or fruit wine) wine (or fruit wine)

(4) Failure to exhaust in time