Bitters (also known as bitter spirits or bitter liqueurs) are spirits with a primarily bitter or bittersweet flavor.
Bitters have an alcohol by volume content of at least 15%. They are primarily enjoyed as aperitifs, digestifs or as an ingredient in cocktails.
In addition to grain alcohol, bitters typically contain herbal extracts (medicinal herbs), citrus plants, tart berries, nuts, licorice extract, angostura bark, cinchona bark, anise and quinine.
Since the “bitter flavor” required by EU regulations is subjective and not clearly defined, the boundaries are blurred. Thus sweet, non-bitter herbal liqueurs are also considered to be bitters even though they can not be officially designated as such according to EU regulations.