What is fermentation primarily defined as?

Fermentation is primarily defined as the chemical action of yeast on sugars. This process occurs when yeast cells convert sugars into alcohol and carbon dioxide in the absence of oxygen, which is a fundamental aspect of many food and beverage production methods, such as brewing beer and making bread.

In this process, yeast metabolizes the sugars present in carbohydrates, generating energy for itself while producing alcohol and carbon dioxide as byproducts. This definition is critical in understanding not just fermentation in a biological context, but also its practical applications in various industries, particularly in food science and alcohol production.

Understanding this definition is crucial because it highlights the role of yeast as a fermenting agent and the substrates (sugars) that are necessary for fermentation to occur.