Vermouth tends to be thought of as an apt blender in a martini—a second thought to making a fine cocktail. Its history as a modern beverage dates back to the 1800s and is celebrated on its own, as well, and as an integral part of a robust food and wine culture in Europe. Recently, the beverage has gained some notoriety as part of the craft spirits boom in the United States. Small-batch vermouth has cropped up across the continent with domestic examples appearing from wine regions in New Yo...