After plenty of experimentation, this is my personal recipe for a Bourbon Sour. What Is a Bourbon Sour? A Bourbon Sour is a variation on the classic Whiskey Sour, made using bourbon as its base spirit. Sour mix can be useful in certain situations, but fresh lemon juice will give you a better and more balanced cocktail. Final ThoughtsThe Bourbon Sour is a simple variation on a classic cocktail, but it is also a great way to explore the differences between bourbons.