The chemical process that changes sugar into alcohol is called fermentation. Fermentation occurs when yeast or bacteria convert sugars, typically from plants, into alcohol and carbon dioxide in the absence of oxygen. This process has been utilized for centuries in producing various alcoholic beverages, including beer, wine, and spirits. During fermentation, the yeast metabolizes the sugars, producing ethanol and releasing carbon dioxide as a byproduct. The specific type of fermentation can vary depending on the substrate (type of sugar) used and the microorganisms involved. It plays a significant role in both food and beverage production, as well as in biofuel development.