The chemical reaction between yeast and sugar produces ethanol and carbon dioxide. The balanced chemical equation for this reaction is glucose/sugar (C6H12O6) in the presence of the yeast enzyme zymase reacts to produce 2C2H5OH (ethanol) +2CO2 (carbon dioxide). This is the ethanol fermentation process used to make beer, wine and bread.
In the fermentation process, sugar breaks down in the presence of the yeast enzyme zymase. The resulting carbon dioxide gas bubbles out into the air, while the alcohol called ethanol is in a mixture with water. However, for fermentation to produce alcohol, it must occur in the absence of air, or else the product formed is ethanoic acid instead. Through the process of fractional distillation, ethanol is extracted from the mixture.