What is the difference between a 'sour' and a 'fizz' in drink classification, and give an example of each?

• A. A sour is carbonated only; a fizz is citrus and sweetness.
• B. A sour is alcoholic only, fizz is non-alcoholic; examples: Whiskey Sour; Lime Fizz.
• C. A sour is dairy-based; a fizz uses nuts.
• D. A sour is citrus-acid with sweetness and a base; a fizz includes carbonation; Examples: Whiskey Sour; Gin Fizz.

Answer: (D)

Sour vs fizz classification hinges on whether carbonation is part of the drink. A sour is built with a base spirit, citrus juice, and a sweetener, creating a tart-sweet balance without carbonation. The texture comes from shaking (and sometimes a foamy egg white), not from bubbles. A Whiskey Sour is a classic example, with whiskey, lemon (or lime) juice, and sugar.

A fizz, by contrast, relies on carbonation as its defining feature. It may still contain a spirit, citrus, and sugar, but the drink is topped with sparkling water or soda to create fizz and a bubbly mouthfeel. A Gin Fizz illustrates this, combining gin, lemon juice, and sugar, then finishing with carbonated water.

So the key difference is carbonation: included in fizz, absent in a sour.