Scotch Sour

Scotch, lemon, and sugar — Thomas's 1862 Bartender's Guide Sour applied to Scotch, Islay peat lending smoke and Highland malt a fruitier result.

The Whiskey Sour is one of the foundational cocktail templates in bartending history, appearing in Jerry Thomas's landmark 1862 Bartender's Guide — the first cocktail manual published in the United States. Thomas's formula of base spirit, lemon juice, and sugar established the sour as a versatile framework that accommodates virtually any spirit. The Scotch Sour substitutes Scotch whisky for conventional American whiskey, transforming the cocktail's character from peppery, grain-driven bourbon or rye to the smokier, more complex profile of Scottish malt whisky. The addition of egg white — which produces the silky foam characteristic of a well-made sour — is optional but widely considered to improve both texture and presentation. Peated Islay Scotch lends a striking smoky dimension, while Highland or Speyside malts produce a gentler, fruitier sour. The Scotch Sour has become a cocktail bar staple as Scotch's global popularity has grown.