What is the main ingredient of a Gin Fizz?

The main ingredient of a Gin Fizz is gin. This cocktail is defined by its use of gin along with other ingredients such as lemon juice, sugar, and carbonated water, which contribute to its refreshing and fizzy character. Gin, with its distinct botanical flavors, provides the foundational taste that defines the drink, making it a classic choice in the cocktail world. In a Gin Fizz, the quality and type of gin used can significantly influence the overall flavor profile, as different gins have unique compositions of botanicals.