Gruit is a herb mixture used for bittering and flavouring beer, popular before the extensive use of hops. The terms gruit and grut ale may also refer to the beverage produced using gruit. Today, however, gruit is a colloquial term applied to a beer seasoned with gruit-like herbs.

Beer is one of the oldest alcoholic drinks in the world, the most widely consumed, and the third most popular drink after water and tea. Beer is produced by the brewing and fermentation of starches from cereal grains—most commonly malted barley, although wheat, maize (corn), rice, and oats are also used. The fermentation of the starch sugars in the wort produces ethanol and carbonation in the beer. Most modern beer is brewed with hops, which add bitterness and other flavours and act as a natural preservative and stabilising agent. Other flavouring agents, such as gruit, herbs, or fruits, may be included or used instead of hops. In commercial brewing, natural carbonation is often replaced with forced carbonation.