Sour drinks are staple cocktails, and within this family, there are two common variations: the sour and the collins. They are related and very similar but have a few key differences.
The Basic Sour
A basic sour is made up of a base spirit plus a sour ingredient, either simple syrup with lemon or a pre-mixed sour. If those components are served in a tall glass with ice and topped with soda, then they create a collins.
For example, a whiskey sour is served in a sour glass (or other short glass) and is a simple mix of whiskey, lemon, and syrup. If that same blend is poured into a collins glass over ice and topped with soda, a John Collins is born. This easy association can be applied to the majority of the most common sour cocktails and with almost any base spirit. The Tom Collins and gin sour both have gin; the vodka Collins and vodka sour, vodka; the Juan Collins and tequila sour, tequila.
The ingredient ratios can be tweaked a little bit to accommodate taste. That is the beauty of any sour: you can always make it your own with a few simple adjustments.
Sours are expansive, and the list is nearly endless. Common variations include those made with absinthe, amaretto, apricot brandy, Grand Marnier, Kahlúa, Midori, rum, and Scotch, as well as those already mentioned.
The Memory Trick for Collins
For the most part, Collins drinks follow suit and define the liquor to use in the name. However, there are two that do not, but they're easy to remember with a little name association.