Vermouth is an acquired taste in the United States, although it’s far more popular in Italy, France and Spain. Drunk as an apéritif or as an essential part of many cocktails — most famously, the Martini — every home bartender worth his bar salt should stock some decent vermouth.
First, the basics. Vermouth is a wine infused with herbs, caramel, sugar, alcohol and water in varying proportions. “Sweet vermouth” presents at 30 to 32 proof, with either a clear or reddish tint. It can have up to 15 percent sugar by volume. “Dry vermouth” clocks in at 36 proof with no more than 5 percent sugar.
Use sweet vermouth for Manhattans, dry vermouth for Martinis. There’s a hybrid beast — the half-sweet vermouth — but its probably best left to professional mixologists.
Gallo and Martini & Rossi manufacture the stock vermouths available at most supermarkets; these varieties are perfectly acceptable for most uses. However, on the theory that it’s best to not ruin a first-class cocktail with third-class ingredients, you may find it helpful to visit a speciality high-end spirits vendor to acquire a bottle of craft vermouth.