Definition for Congener
From Biology Forums Dictionary
In the alcoholic beverages industry, congeners are substances produced during fermentation. These substances include small amounts of chemicals such as other alcohols (known as fusel alcohols), acetone, acetaldehyde, esters, and aldehydes (e.g. propanol, glycols, ethyl acetate). Congeners are responsible for most of the taste and aroma of distilled alcoholic beverages, and contribute to the taste of non-distilled drinks. It has been suggested that these substances contribute to the symptoms of a hangover.