Ethanol fermentation causes bread dough to rise. Yeast organisms consume sugars in the dough and produce ethanol and carbon dioxide as waste products. The carbon dioxide forms bubbles in the dough, expanding it into something of a foam.Nearly all the ethanol evaporates from the dough when the bread is baked.n ethanol fermentation, one glucose molecule breaks down into two pyruvates (1). The energy from this exothermic reaction is used to bind inorganic phosphates to ADP and convert NAD+ to NADH. The two pyruvates are then broken down into two acetaldehydes and give off two CO2 as a waste product (2).