Whisky Sour vs. Scotch Sour: What Sets Them Apart?

scotch sour in old fashioned glass with lemon slice

The Whisky Sour is a classic cocktail, striking a balance between rich spirit, fresh lemon, and a touch of sweetness. But not all whisky sours are created equal—especially when you swap out bourbon for Scotch. The resulting drink, the Scotch Sour, takes on a character all its own. The main difference comes down to the base whisky, which defines the flavor, aroma, and finish in every sip.

Base Spirits: The Core Distinction

A true Whisky Sour usually involves American whiskeys—traditionally bourbon, sometimes rye—whereas a Scotch Sour uses Scotch whisky as its foundation. Both are sub-types of sour cocktails, but their base spirits lead to noticeably different drinking experiences. Here’s how the two compare:

Bourbon (Whisky Sour): known for its caramel, vanilla, and soft spicy notes. Bourbon’s sweet corn base and new oak aging create a smooth, approachable flavor.
Rye Whiskey (alternative base): adds extra spice, dryness, and punch—making for a sharper and more robust sour.
Scotch Whisky (Scotch Sour): the flavor can be sweet, malty, smoky, or peaty, depending on the region and style. Peated Scotch brings earthiness, while a mild Speyside presents honey and orchard fruit.

Flavor Profiles: Complex vs. Comforting

A whisky sour made with bourbon offers warming vanilla, light spice, and a rounded sweetness that supports the fresh lemon and sugar. With Scotch, the entire profile shifts: you might encounter smoky peat, briny notes, or honeyed malt—but always with a lush citrus backbone from lemon juice. Ingredients stay nearly identical; it’s the whisky’s personality that shines through.

Bourbon Whisky Sour: full-bodied, smooth, sweet with a touch of wood and caramel—a crowd-pleaser even for newcomers.
Scotch Sour: lighter style Scotch brings floral, malty, and green fruit notes; smoky Islay delivers earth, ash, and sea and stands up boldly against citrus.

classic whiskey sour with foam in coupe glass

How Does Sour Mash Whisky Fit In?

Sour mash is a fermentation process used primarily in bourbon and Tennessee whiskey production, where a portion of a previous batch's mash is reused to start the new one. This technique helps maintain consistency and tempers the mash’s acidity. Sour mash whiskey is always American, smoother and softer, but it’s not a different style of sour cocktail—it’s just a production method. In a whisky sour, any bourbon or rye labeled 'sour mash' will work just as well.

Scotch Sour vs. Whiskey Sour: Which Should You Try?

Want richness and comforting flavors? Choose a classic bourbon whisky sour for accessible sweetness.
Craving complexity and a touch of savory or smoke? Reach for a Scotch sour—just start with a milder Scotch, then test peatier options as your palate evolves.

Scotch Whisky Sour Recipe (Standard Proportions)

60 ml Scotch whisky (try a mellow blended or Speyside single malt for balance)
22.5 ml fresh lemon juice
15 ml simple syrup
Optional: 15 ml egg white or aquafaba for foam
Garnish: lemon wheel or twist

Add Scotch whisky, lemon juice, simple syrup, and (if using) egg white to a shaker.
Dry shake hard for 10 seconds (if using egg white).
Add ice and shake again until well chilled.
Strain into an old fashioned glass with fresh ice.
Garnish with a lemon wheel or twist.

scotch whisky sour next to bourbon sour on bar

Points to Remember

The whisky sour and Scotch sour only differ in the base spirit—everything else is about personal taste.
Scotch brings a more layered, sometimes smoky dimension, while bourbon offers a mellow sweetness.
Both styles shine with fresh lemon, balanced sugar, and quality ice.