What ingredient is NOT part of the Whiskey Sour cocktail?

The Whiskey Sour is a classic cocktail primarily made with whiskey, lemon juice, and a sweetener (typically simple syrup). One of the options listed that does not belong in the traditional recipe is ginger beer, which is generally associated with cocktails like the Moscow Mule or Dark 'n' Stormy. The addition of ginger beer would alter the flavor profile of a Whiskey Sour, significantly changing its character from a tart and whiskey-forward drink.

Lemon is an essential ingredient, providing the sourness that defines the cocktail. Egg whites may also be included in variations of the Whiskey Sour for added texture and a frothy top. Meanwhile, an Amarena cherry often serves as a garnish, enhancing the drink's presentation and flavor without being a core ingredient. Thus, while lemon, egg whites, and Amarena cherry all play roles in various interpretations of the Whiskey Sour, ginger beer clearly does not fit within this particular cocktail's definition.