What is the common ratio for a classic sour cocktail?

In a classic sour cocktail, the standard ratio is typically 2 parts spirit to 1 part sour. This means that for every two parts of the primary spirit used (like whiskey, rum, or gin), you would use one part of a sour component, which usually includes fresh lemon or lime juice and often sugar or simple syrup to balance the acidity. This combination creates a balanced and flavorful drink with a robust spirit presence complemented by the tartness of the sour.

The reasoning behind this specific ratio is that it allows the spirit to shine through while still providing sufficient acidity and sweetness to create a harmonious flavor profile. If the proportions were altered to include more sour than spirit, or a 1:1 ratio, the cocktail would be too tart, losing its spirit-forward character, which is essential in a classic sour.