Fermentation

Fermentation allows yeast to respire anaerobically and is used commercially to manufacture bread and alcoholic drinks.

In bread-making, carbon dioxide from yeast fermentation forms bubbles that make dough rise; in brewing, ethanol is the desired product.

Yeast fermentation is useful in bread-making because the carbon dioxide forms bubbles that make dough rise. The ethanol and carbon dioxide are both products of the reaction; they are not made by anaerobic respiration in animal muscle.