The Negroni traditionally combines gin, sweet vermouth and Campari in equal parts.
The cocktail is commonly linked to Count Camillo Negroni, who reportedly asked for gin instead of soda water in an Americano at Caffè Casoni in Florence around 1919. The substitution made the drink stronger while preserving the bitter, sweet and aromatic structure of its predecessor.
A classic Negroni is stirred with ice and strained over fresh ice, usually in a rocks glass. An orange peel is the standard garnish, and its oils add a bright citrus aroma. Exact proportions can vary in modern bars, but the equal-parts formula is the widely recognized classic.
The Americano contains Campari, sweet vermouth and soda water. The Boulevardier replaces the Negroni’s gin with whiskey, making those neighboring cocktails easy to confuse.