As bartenders rediscover and reinterpret classic cocktails, there has been confusion over the difference between a whiskey sour and a whiskey fix. Traditional versions of the sour and fix cocktails were nearly identical since both came from punch-style cocktails, but they have one key difference.

Even when glamorized, the whiskey fix drink retains the distinguishing on-the-rocks quality of a punch, and the oldest recipe contained only sugar, water, lemon juice, and a glass of whiskey with shaved ice. Therefore, in one of their earliest iterations, the difference between a sour and a fix is simply ice.

The most basic version of the whiskey sour has only spirit, citrus, and sugar, but some early innovators added an egg white, which can froth due to the lack of ice. Whiskey sours have become much more popular than whiskey fixes, and whiskey sours are now essential to mixology.