How Gin Works

By: Dave Roos  | 

Gin & Tonics, Prohibition and All That Jazz

police, gin labels, confiscated
Police display gin labels and presses they confiscated in 1921 during Prohibition. Bettmann/Getty Images

The characteristic flavor of London dry gin is the product of 19th century imperial expansion. Juniper strikes the strongest note, but the taste of a classic London dry gin is created by a blend of a dozen or more botanicals sourced from exotic ports as far away as Africa, China and South America.

In 1868, a typical London dry gin recipe might include: juniper, sweet fennel, orange peel, orange flower water, coriander seed, angelica root, calamus root, cassia buds, lemon peel, cardamom, oil of cedar, sweet almonds, nutmeg, mace, caraway seed, wintergreen and honey.


But one of the most fascinating byproducts of 19th century British imperialism is how the rigors of international sea travel and the health challenges of tropical colonial living led to the invention of classic gin cocktails like the gin and tonic, the pink gin and the gimlet.

First, the gin and tonic. Malaria was a plague on sailors and British colonists living in tropical climates. For centuries, natives of South America chewed on the bark of the chinchona tree to combat the symptoms of malaria. The bark contains a natural chemical called quinine that not only calms the muscle aches and spasms caused by malaria, but disrupts the malaria parasite's metabolism, eventually killing it.

When European doctors got wind of this, they began prescribing prophylactic chinchona bark to British soldiers and colonists in India. In the 1840s, British soldiers and settlers were consuming 700 tons (635 metric tons) of chinchona bark a year.

A water-soluble form of quinine was invented in the 1850s, which lead to the bottling of the first "Indian quinine tonics," the earliest tonic waters. Schweppes was one of the first big bottlers of carbonated tonic water.

Meanwhile, the British Navy was sailing to every port in the world and bringing bottles of London dry gin with them. It was only a matter of time before officers and colonists began combining their favorite tipple with a shot of tonic water for their health. And the gin and tonic was born!

The same with bitters. Bitters were first prescribed up as a curative tonic for gout in the 18th century. But by the 19th century, bitters were being sold as a cure-all for a host of travel-related ailments related to long sea journeys and life in tropical climates. The basic recipe for bitters is bitter orange peel, oil of carraway, cardamom, oil of wormwood and plenty of sugar.

A German named Johann Siegert moved to Venezuela in the 1820s to serve as the surgeon general in a revolutionary army. He settled in the town of Angostura and began producing his own brand of bitters for treating his soldiers for seasickness and digestive ailments. In the 1830s, he started bottling and selling his now-famous angostura bitters.

Soon British sailors worldwide were downing "medicinal" cocktails of London dry gin and a shot of Angostura Bitters, or what's known as a pink gin.

And then there's scurvy, the deadliest scourge for long-haul sailors. Over the 18th century, it's estimated that scurvy killed more British soldiers than the French. Scurvy is caused by a vitamin C deficiency that brings on a host of nasty symptoms: lethargy, bleeding gums, teeth fall out, old wounds reopen, loss of sensation in the limbs. It killed sailors in droves.

Scurvy can be easily cured with citrus fruit, but fresh citrus doesn't last long aboard a ship. Sailors tried to boil and condense lime juice, but the process cooked out the vitamin C. Eventually, a Scottish scientists named Lachlan Rose figured out a way to preserve lime juice by mixing it with a small quantity of sulphur dioxide. Rose's Lime Juice became a shipboard staple, and it wasn't long before it was being mixed with gin to make a classic gimlet.

(There are competing stories about the naming of the gimlet. Other sources say it might be named after Sir Thomas Gimlette, surgeon general to the British Navy, or the screwdriver-like hand tool used to open barrels of lime juice.)

Prohibition and "Bathtub Gin"

While the British colonists were enjoying their first mixed drinks, Americans were brewing up a cocktail culture of their own. By the Civil War (1860s), American-style cocktails were characterized by various combinations of liquor, bitters and sugar water and went by names like "gin-sling, sangaree, mint julep, sherry-cobbler and timber doodle."

The classic gin martini showed up in the 1870s and 1880s. From Richard Barnett, author of "The Book of Gin: A Spirited World History from Alchemists' Stills and Colonial Outposts to Gin Palaces, Bathtub Gin, and Artisanal Cocktails": The martini is "an embodiment of American history at its most diverse: Dutch and English gin, mixed with French vermouth, and served with Mediterranean olives, German-Jewish pickled onions or Caribbean lemons." The distinctive conical martini glass was popularized in the first decade of the 20th century.

But the real American cocktail boom was spurred by the passing of Prohibition in 1920. With a ban on the production and sale of alcohol, the booze industry went underground, and gin is one of the easiest spirits to make on the cheap.

The 1920s were like the Gin Craze all over again. Bootleggers would do anything to get their hands on grain alcohol. That included backdoor deals with industrial alcohol manufacturers and buying up moonshine from backwoods stills. Once you have the grain alcohol, it's a quick step to making gin. You could simply add water and juniper oil, but some folks were going back to the Gin Craze days of spiking grain alcohol with turpentine oil and sulphuric acid.

For Prohibition partiers, gone was the clean, piny finish of a London dry gin. Instead, they got "bathtub gin," a colorful nickname that alluded to its homemade origins and dirty aftertaste. But no worries, because even the foulest tasting bathtub gin could be covered up by a combination of strong bitters, citrus and simple syrup.

The martini, the Manhattan, the gin fizz, the gimlet: Jazz-Age Americans were crazy over cocktails, and after Prohibition ended in the 1930s, cocktail parties became the fashionable way to entertain.