A liqueur is an alcoholic beverage made from a distilled spirit that has been flavored with fruit, cream, herbs, spices, flowers or nuts and bottled with added sugar or other sweetener (such as high-fructose corn syrup). Liqueurs are typically quite sweet; they are usually not aged for long after the ingredients are mixed, but may have resting periods during their production to allow flavors to marry.
In the United States and Canada, where spirits are often called “liquor” there is often confusion over liqueurs and liquors, especially as many spirits today are available in flavored form (e.g. flavored). The most reliable rule of thumb is that liqueurs are quite sweet and often syrupy in consistency, while liquors are not. Most liqueurs have a lower alcohol content (15–30% ABV) than spirits, but some contain as much as 55% ABV.
In parts of the United States, liqueurs may also be called cordials or schnapps, while in large parts of the British Commonwealth, cordial means a concentrated non-alcoholic fruit syrup that is diluted to taste and consumed as a non-carbonated soft drink, and in Germany and Scandinavia, schnapps means a form of brandy or aquavit.
Liqueurs are historical descendants of herbal medicines; they were made in Italy as early as the 13th century and were often prepared by monks (e.g. Chartreuse).
Nowadays, liqueurs are made worldwide and are served in many ways: by themselves, poured over ice, with coffee, mixed with cream or other mixers to create cocktails, etc. They are often served with or after a dessert. Liqueurs are also used in cooking.
Some liqueurs are prepared by infusing certain woods, fruits, or flowers, in either water or alcohol, and adding sugar or other items. Others are distilled from aromatic or flavoring agents. Anise liqueurs have the interesting property of turning from transparent to cloudy when added to water: the oil of anise remains in solution in the presence of a high concentration of alcohol, but crystallizes when the alcohol concentration is reduced; this is known as the ouzo effect.
Layered drinks are made by floating different-colored liqueurs in separate layers. Each liqueur is poured slowly into a glass over the back of a spoon or down a glass rod, so that the liquids of different densities remain unmixed, creating a striped effect.
The word liqueur comes from the Latin liquifacere (“to liquefy”).