Why a Negroni is equal parts: the spec and a ratio builder

The Negroni is the simplest spec in the book: equal parts gin, Campari and sweet vermouth, built over ice. It looks like a guess, but it is a balance, because each bottle fixes a flaw in another.

Slide the three parts in the builder to see the glass, each bottle's share and a rough strength, then add or cut dilution with the stir. It also covers the popular origin story, how to fix a Negroni that tastes off, and lighter and alcohol-free versions.