Whisky Sour

The Whisky Sour is a cocktail defined by the combination of whisky, lemon juice, and a sweetener, typically simple syrup. The International Bartenders Association (IBA) specifies a recipe of 45 ml whisky, 25 ml fresh lemon juice, and 20 ml simple syrup, shaken with ice and strained into a rocks glass over fresh ice, optionally garnished with a cherry and an orange slice. The drink is often served with an egg white foam, a variation that adds a silky texture and a creamy head, though this is not part of the IBA specification.

The sour is one of the oldest families of cocktails, with the first printed reference to a "whiskey sour" appearing in the 1870s. The Jerry Thomas' 1862 "Bar-Tender's Guide" included a "Whiskey Sour" recipe, though it predates the use of egg white in sours, which became popular later.¹ The drink likely evolved from the British naval practice of mixing spirits with citrus to prevent scurvy, and the term "sour" was used to describe drinks with citrus and sugar.

Numerous variations exist, including the use of different whiskies: bourbon gives a sweeter, fuller body, while rye adds a spicier edge. Some recipes substitute the simple syrup with maple syrup or honey. The addition of egg white is common in craft cocktail bars, creating a frothy top. A notable variant is the "New York Sour," which floats a layer of red wine on top.² Other variations include the "Boston Sour" (with egg white) and the "Sazerac Sour" (with absinthe rinse).

The Whisky Sour has appeared in popular culture, including films like "The Thin Man" (1934) and "The Long Goodbye" (1973). It is a standard in cocktail bars and is often used as a benchmark for a bartender's skill. In 2019, the Whisky Sour was ranked among the top 10 most popular cocktails in the world by Drinks International.³

One lesser-known fact is that the Whisky Sour was a favorite of President Harry Truman, who often served it at the White House. Another is that the original sours were often made with a "sour mix" of lemon and lime, but modern mixology emphasizes fresh juice. Additionally, the use of egg white in sours has a scientific basis: the protein in the egg white creates a stable foam when shaken, a technique that was popularized in the late 19th century. In some historical recipes, the egg white was omitted, but the drink was still called a sour, leading to debates about what constitutes a true sour.

Sour

A family of cocktails that combine a base spirit with lemon or lime juice and a sweetener.

Simple syrup

A sugar-water solution used to sweeten cocktails, typically equal parts sugar and water.

Egg white

The clear liquid of an egg, used in cocktails to add texture and create a foam when shaken.

Rye whisky

A type of whisky made primarily from rye grain, known for its spicy flavor.

Bourbon

An American whisky made from at least 51% corn, with a sweeter, fuller flavor.