The term "bitter" refers to alcoholic spirits with a distinct bitter flavor. These spirits have a minimum alcohol content of 15% by volume. The distinction between liqueurs and bitters is not always straightforward. Occasionally, herbal liqueurs are also referred to as bitters, though this may not always be accurate. The bitter taste of these specialty spirits is attributed to the spices and herbs used in their production. Bitters are especially well-liked as both an aperitif and a digestif.