The most varied and versatile category of spirits is arguably liqueurs, which includes everything from Baileys Irish Cream and Cointreau to Campari and Jägermeister. In the U.S., the term “liqueur” is synonymous with cordials and is derived from the Latin liquefacere, meaning to liquefy. It refers to the early Middle Ages monastic practice of extracting the essence of botanicals, which were added to base spirits and believed to have medicinal properties. Even though these concoctions all taste completely different, their basic recipe is fairly similar: alcohol and sugar (according to US law, a liqueur must contain at least 2.5 percent sugar by weight), plus spices, herbs, flowers, fruit, nuts, cream, or other flavorings. Many brands boast long histories, and a number of recipes are still secret.
Though some liqueurs are sipped neat or on the rocks (or poured as shots), they’re more commonly mixed with other types of spirits in cocktails.
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.
Liqueurs can be hard to classify, but regardless of flavor they can be broadly divided into two categories: generics and proprietaries.
Generics are liqueurs of a particular type (Crème de Cacao or Curaçao, for example) that can be made by any producer.
Proprietaries are liqueurs with trademarked names that are made according to a specific formula. Examples of such liqueurs include Kahlúa, Grand Marnier, and Southern Comfort.
Schnapps is a general term used for an assortment of white and flavored spirits that have originated in northern countries or regions such as Germany or Scandinavia. Schnapps can be made from grain, potatoes, or molasses and be flavored with virtually anything (Watermelon and Root Beer Schnapps from the United States being proof of that). The dividing line between Schnapps and Flavored Vodka is vague and is more cultural than stylistic, although European Schnapps tend to be drier than their American counterparts and liqueurs.
Anise-Flavored Spirits can vary widely in style depending on the country of origin. They can be dry or very sweet, low or high proof, distilled from fermented aniseed or macerated in neutral spirit. In France, Anis (as produced by Pernod) is produced by distilling anise and a variety of other botanicals together. Pastis is macerated, rather than distilled, and contains fewer botanicals than Anis. In Italy, Sambucca is distilled from anise and botanicals, but is then heavily sweetened to make it a liqueur. Oil of fennel (also known as green anise) is frequently added to boost the aroma of the spirit. Greece has a drier, grappa-like liqueur called Ouzo , which is stylistically close to pastis.
Bitters are the modern-day descendants of medieval medical potions and are marketed as having at least some vaguely therapeutic value as stomach settlers or hangover cures. They tend to be flavored with herbs, roots, and botanicals, contain lower quantities of fruit and sugar than liqueurs, and have astringent notes in the palate. Note, these are bitters liqueurs that can be drunk on their own, not cocktails bitters which lack sugar and are designed for accenting cocktails and culinary creations. Classic bitters liqueur examples include: Campari, Aperol, and Suze.