What are substances known as that are present in an alcoholic beverage besides alcohol and water?

Congeners are substances that are produced during fermentation and are found in alcoholic beverages alongside alcohol and water. These compounds can include a variety of chemicals, such as tannins, fusel oils, and other flavor compounds, which contribute to the taste, aroma, and character of the beverage. They also play a role in how the body metabolizes alcohol and can affect the severity of hangovers.

Unlike the other options, which refer to specific types of additives or compounds with their own distinct functions, congeners are naturally occurring byproducts of the fermentation process in alcoholic beverages. Allergens, for example, refer to substances that cause allergic reactions and are not exclusive to alcoholic beverages. Preservatives are added to extend shelf life and prevent spoilage, and colorants are added to enhance or change the appearance of the beverage, but these are not integral components of the fermentation process itself. Thus, congeners directly relate to the inherent qualities of the beverage.