The Oxford Companion to Spirits and Cocktails Definition of citrus

citrus refers to a fruit group known as hesperidia, characterized by segments containing juice-filled vesicles held together by a spongy pith (albedo) and surrounded by a leathery peel, generally containing a high concentration of aromatic oils in the outermost layer (flavedo); the juices and the oils are among the most important non-alcoholic ingredients in mixed drinks. Current taxonomy is debated here, but commonly used citrus fruits are descended from either three or four parent species: citron, mandarin, and pomelo, with papeda as a probable ancestor as well. The citrus varieties used most often in cocktails—lemons, limes, oranges, and grapefruit, roughly in that order—are typically a cross between two of these parent species.

Citrus is used in cocktails primarily as an acidifier, although each variety adds its own flavor. See acidity. For citrus-driven drinks, the more sweet ingredients such as syrups and liqueurs are used, the more citrus needs to be added to create balance. See balance. Lemon and lime are the most acidic and the lightest in flavor; grapefruits can range widely in their acidity; and oranges are the sweetest and often benefit from the addition of lemon or lime to bolster their acid. Citrus fruits contain both citric acid and ascorbic acid (vitamin C). Refined citric acid can be used in cocktails to replace fresh juice and is the typical acidifier in bottled tonic water. Citric acid on its own provides sourness without a distinct flavor. Other, less common acidifiers include lactart (lactic acid, found in dairy and lambic beer), malic acid (found in apples, grapes, and rhubarb), and acid phosphate (partially neutralized phosphoric acid with mineral salts added, used in cola and some soda fountain drinks). See lactart and phosphate.

Citrus oil, dispersed across the surface of a drink by twisting a strip of zest a few inches above the surface and rubbing the rim of the glass with it, is a common garnish for Martinis, Old-Fashioneds, and other aromatic stirred drinks. The oil can also be extracted mechanically or by macerating citrus zest in sugar. See sugar. Sugar is hygroscopic and will draw out the moisture in the zest when left in contact for several hours. The resultant liquid is called an oleo-saccharum, an oil and sugar mixture. See oleo-saccharum. Traditional punch is started by making an oleo-saccharum, usually with the zest of the citrus juice that will be included in the drink. See punch.

Varieties of Citrus

Citron, one of the parent species of both lemons and limes, is a large, thick-skinned citrus variety used primarily for its pith. The flavedo, or zest, is highly aromatic and used in perfumery. See zest. The flesh is proportionately small and dry with many seeds. Its most common use is candying or glacéing the pith, then serving in wedges or dicing for use in fruitcakes or other desserts. Buddha’s hand, also called fingered citron, is an unusual and beautiful variety prized for its aroma and brought to prominence in the spirits world when St. George Spirits released its Hangar One vodkas. See St. George Spirits. In Jewish culture, citron plays a vital part in the holiday of Sukkot.

The mandarin, parent of the orange and grandparent of the grapefruit, is the sweetest of the four original citrus varieties. This characteristic is the reason it has been used in so many common hybrids, including the satsuma, Meyer lemon, rangpur lime, and clementine. Mandarins are most often eaten fresh and are characterized by a thin, weak pith, making them easy to peel. The peel can be dried and used as a spice. Mandarin juice is rarely called for in cocktails.

Papeda is native to Asia and responsible for many of the exotic citrus hybrids coming out of that part of the world, like yuzu, kaffir lime, and sudachi. Papeda itself is bitter and generally not used for eating but lends important characteristics for rootstock and breeding.

The lime used by today’s bartenders is the Persian lime, also known as the Bearss lime, developed by John T. Bearss in California in 1895. He bred them to be larger and hardier than the key lime, without seeds and with a greater juice yield. Ironically, key limes were the variety cultivated in Persia, but when Columbus brought them to America via the Florida Keys, they were renamed. The key lime was the only widely available lime variety for centuries, until hurricanes decimated Florida’s groves in 1926 and 1928. The Persian lime filled the void and has been the common lime used in cocktails in the United States ever since. In the rare instances of pre-1930s American cocktails that call for limes, key limes are the variety that would have been used. Cocktails from tropical climates almost always use key limes.

Key lime juice is both sweeter and more acidic than Persian lime juice and is higher in aromatic compounds that are associated with sweet things, like vanilla and strawberries. When substituting one for the other, less key lime juice, and therefore less sweetener, is necessary to create a balanced cocktail.

Lemon, a cross between a sour orange and a citron, is historically the most common source of citrus juice called for in cocktails, as limes were not widely available until the 1930s. Lemons, cultivated in the Middle East and the Mediterranean for a thousand years, were part of Columbus’s freight and were then disseminated throughout the Caribbean. Along with sour, or “Seville,” oranges, lemons were the original souring agent for punch and had the additional advantage of being a potent antiscorbutic, something known to British sailors as early as 1601 and only acknowledged by the British Admiralty in 1794, after which punch was issued to all sailors.

In cocktails, certain spirits lend themselves better to lemon rather than lime juice, especially whisky. See whisky. One category of drinks, the ginger highball, which includes Bucks and Mules, is frequently distinguished only by the use of lemon juice for Bucks and lime for Mules, although these titles are not firm; modern bartenders tend to use the terms interchangeably. See Buck.

Grapefruit, crossed from pomelo and mandarin, has a stronger flavor than lemon or lime, slightly less acidity, and a higher sugar content. Darker, redder fruits are sweeter than pale varieties.

“Ruby” varieties of grapefruit originated by treating grapefruit bud stems with radiation, then selecting and breeding the varieties that mutated with the richest color. Unlike genetically modified organisms, radiated crops show no evidence of manipulation. Mutant ruby grapefruit now accounts for 75 percent of all grapefruit grown in Texas, the second largest producer of grapefruit in the United States. See whisky, Irish, and whisky, scotch.

When using grapefruit as the sole acidifier in a drink, more juice is necessary to add enough acid to balance a cocktail’s typical sugar content. Because grapefruit itself is sweeter than lemon or lime, less added sweetener is required. Thus, grapefruit cocktails tend to be more focused on the flavor of the fruit than drinks using lemon or lime as the acidifier.

Oranges, crossed from pomelo and mandarin, are grouped into two categories: sweet and bitter/sour. Sweet oranges, like Valencia and navel, are used for juice and eaten fresh. Bitter/sour oranges are typically used for their aromatic zest.

Sweet Oranges

Navel oranges are a sweet orange seedless clone, grown through grafting, and are firmer and easy to peel and therefore are best eaten fresh. Due to higher concentrations of limonin and other bitter phytochemicals, plus the firmer texture of the flesh, juice yields from navel oranges are low, and it degrades more quickly.

Valencia oranges were hybridized in the mid-1800s in Santa Ana, California, and named for Valencia, Spain, which is known for its sweet oranges. The juice quality and yield are very high. Valencias are the most popular juicing orange in the United States, and it is the most common juice used in cocktails.

Bitter Oranges

Bitter/sour oranges include the Seville, chinotto, and bergamot varieties. The zest of bitter oranges is high in essential oils, bitter, and very aromatic, and it is also used in perfumery and cleaning products. Seville oranges, generally only available in winter, are high in pectin and are prized for making marmalade. Sour orange juice is rarely used in the United States but is sometimes used in cooking in Central and South America. In the eighteenth century, however, it was considered the best citrus juice for making punch. See Ashley, James. The rangpur lime is often mistaken for a sour orange due to its orange flesh, but it is in fact a variety of lime.

The bergamot orange is a hybrid; its oil is an analgesic and antiseptic, and it is used to flavor Earl Grey tea. See tea. Chinotto oranges are used to flavor an Italian soda brand of the same name, owned by San Pellegrino.

The peel from bitter orange varieties is used to make orange bitters, and it is often included in aromatic bitters as well. Orange bitters often use sweet orange peel as well as bitter.

Orange flower water (also called orange blossom water) is made by water-distilling orange blossoms. See orange flower water and essential oils. Orange flower water is used in a Ramos Fizz and is a common ingredient in Orgeat, the almond syrup used in the Mai Tai and the Japanese Cocktail. See Japanese Cocktail; Mai Tai; Orgeat; and Ramos Fizz. Orange flower water was also used to flavor capillaire, a defunct cocktail syrup made from maidenhair fern. See capillaire.

citrus

Varieties of Citrus

Sweet Oranges

Bitter Oranges

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