liqueur, flavoured and sweetened distilled liquor, with alcohol content ranging from 24 percent to 60 percent by volume (48–120 U.S. proof). Liqueurs are produced by combining a base spirit, usually brandy, with fruits or herbs and are sweetened by the addition of a sugar syrup composing more than 2 1/2 percent of the total beverage by volume.

The word liqueur is derived from the Latin liquefacere, meaning “to make liquid.” Liqueurs were probably first produced commercially by medieval monks and alchemists. They have been called balms, crèmes, elixirs, and oils and have been used over the centuries as medicines and tonics, love potions, and aphrodisiacs.

Fruit liqueurs are produced by the infusion method, in which fruit is steeped in the spirit, which absorbs aroma, flavour, and colour. Plant liqueurs, naturally colourless, are produced by either percolation or distillation. Percolation is accomplished in an apparatus much like a coffee percolator. Leaves or herbs are placed in the top section, and the base spirit in the bottom section is pumped up over the flavouring material, extracting and carrying down the flavour constituents. The distillation method uses plants, seeds, roots, or herbs as flavouring material. They are softened in the base spirit, then combined with additional spirits and distilled. After the base spirit is completely flavoured, it is sweetened and filtered. Plant liqueurs are frequently coloured with vegetable colourings. Liqueurs may be aged or bottled immediately.

Generic liqueurs, marketed under accepted common names, frequently vary according to brand because of formula differences. They include apricot liqueur; crème d’ananas, flavoured with pineapple; crème de cacao, flavoured with cocoa and vanilla beans; crème de framboises, made from raspberries; crème de menthe, mint-flavoured; crème de noyaux, with bitter-almond flavour derived from fruit stones; crème de violette, also called parfait amour, with oils from both violets and vanilla beans; Curaçao, with flavour from the dried peel of the green oranges of the island of Curaçao; Danziger Goldwasser, spicy and containing tiny gold specks; kümmel, flavoured with caraway seed; prunelle, with plum flavour; sloe gin, flavoured with the fruit of the blackthorn bush; and Triple Sec, a colourless Curaçao.

Proprietary brands, usually prepared from secret formulas, are made by individual producers, who market their products under registered brand names. French proprietary brands include Bénédictine, a plant liqueur first produced in 1510 from one of the most closely guarded of all formulas; Chartreuse, made from a formula developed in 1607, including yellow and green plant liqueurs, both with spicy and aromatic flavour; Cointreau, a proprietary brand of Triple Sec; Grand Marnier, produced in the Cognac region, an orange Curaçao; and Vieille Cure, a plant liqueur made in Bordeaux. Italian liqueurs include Liquore Galliano and Strega, both with spicy flavours. British brands include Drambuie, with Scotch whisky as a base and flavoured with honey, made from a French formula taken to Scotland in 1745; and Irish Mist, a spicy liqueur made with Irish whiskey and honey. Cherry Heering is a cherry liqueur produced in Denmark. Liqueurs manufactured in the United States include Forbidden Fruit, made with brandy and grapefruit; and Crème Yvette, with violet flavour and colour. Coffee-flavoured brands include Kahlúa, from Mexico; and Tia Maria, using rum as the base spirit, from Jamaica. O Cha, with the flavour of green tea, and Midori, with the flavour of melon, are from Japan. Van der Hum is a spicy and aromatic product made in South Africa.

Liqueurs, sweet in flavour and with ingredients promoting digestion, are popular after-dinner drinks. They may be served straight, poured over ice, or mixed in an endless variety of combinations that may include liquors, brandies, and cream. Liqueurs are also used as flavourings in various dessert dishes.