What is produced as a by-product of alcoholic fermentation?

During alcoholic fermentation, yeast and some types of bacteria convert sugars into alcohol and carbon dioxide in the absence of oxygen. This process primarily involves the breakdown of glucose, where it is transformed into ethanol (alcohol) and carbon dioxide as by-products. Carbon dioxide is the gas that is released during this fermentation process, which can be observed in the bubbling of fermenting beverages, such as beer and wine.

The production of carbon dioxide plays a significant role in the fermentation process, especially in baking, where it helps dough rise. This is distinct from lactate production, which occurs during lactic acid fermentation, and from NADH, which is a carrier of electrons used in cellular respiration. Oxygen is not produced during fermentation; in fact, it is the absence of oxygen that defines this anaerobic process. Thus, the by-product of carbon dioxide is a key indicator of alcoholic fermentation.