The Scotch Sour is a classic cocktail made with a combination of Scotch whisky, lemon juice, sugar, egg white, and sometimes bitters. It’s simply a spirit-specific version of the Whiskey Sour, a cocktail that can be made with any type of whiskey, but modern iterations at bars in the United States tend to employ bourbon unless specified otherwise.
Though the change seems minor, the vast difference in flavor profiles between scotch and other forms of whisk(e)y creates an entirely different cocktail.
The Sour category of cocktails is one of the oldest around, and typically involves a base spirit mixed with some form of tart citrus (usually lemon or lime juice) and a sweetening agent (like sugar, syrup, or liqueur) to create balance. The term itself can be preceded by any spirit type, and drinks like the Gin Sour and Brandy Sour have been enjoyed for over a century, though their popularity has generally been eclipsed by that of the Whiskey Sour.
While domestically produced whiskeys created with corn, rye, and wheat dominated the U.S. market prior to the 1900s, Prohibition’s ban on alcohol created an additional demand for Scotch whisky. Though it was smuggled into the country illicitly during this period (generally through the Bahamas, which was a British colony at the time), scotch’s foothold in America lasted far beyond Prohibition’s repeal, and only grew as exports of the spirit increased after World War II.
An outsized number of Whiskey Sours mixed in the latter half of the 20th century may have been made with scotch, but a glut in the whisky’s production (alongside a large number of scotch imitations) met a degradation of the cocktail itself, when pre-made “sour mix” increasingly took the place of fresh ingredients.
What was once one of the oldest styles of cocktail often became a slug of scotch-flavored spirit combined with a three-second push of the “sour” button on a soda gun.
As the millennium turned, U.S. whiskey production exploded, as did the resurgence of classic-style cocktails using their original ingredients. The Whiskey Sour became respectable again, and though it was increasingly made with bourbon, the Scotch Sour never truly went away. In fact, the drink became the basis of a new wave of modern classics, namely the Penicillin, a culture-changing cocktail from New York City’s Milk & Honey. This drink uses the Scotch Sour template but includes honey rather than simple syrup, and utilizes an additional float of heavily peated single malt scotch to highlight the full array of the spirit’s flavors.
The combination of spirit, citrus, and sugar is so ingrained in cocktails because of how well the combination works across a wide range of ingredients. But what you get from the Scotch Sour is a predominantly malt-forward flavor that helps to create an earthiness not often found in sweeter, bourbon-based versions of the drink.
Blended scotch tends to be the ideal whisky for a Scotch Sour, though a single malt can work as well. However, if the goal is to increase the peat and smoke elements of the drink, a variation like the Penicillin may be more ideal, where a single malt float allows for more of those elements to come through on the nose with each sip instead of getting blunted into submission by shaking.
Though a Scotch Sour can effectively be made using just the three primary components (whisky, lemon juice, sugar), many Sours include egg white to create a creamier texture and rounder mouthfeel. This is optional and can be skipped for a cleaner tasting drink.
We do, however, include two dashes of Angostura bitters here, which help accentuate some of the deeper and more tannic elements of blended scotch that can be lost in mixing the drink, bringing them back to the forefront. If using a more heavily peated whisky, the bitters can safely be omitted.
Add Scotch whisky, lemon juice, simple syrup, Angostura bitters, and egg white (if using) to a shaker, and dry-shake for 30 seconds without ice.
Add ice and shake again for 15–20 seconds, until well-chilled.
Strain into a rocks glass over fresh ice.
Garnish with an orange twist.
