The days when Campari was the only Italian red bitter you'd likely find at an American bottle shop or bar are now a distant memory. Today, liquor store shelves are lined with a constantly expanding selection of aperitivi and bitters in a Pantone color swatch spectrum of scarlet, crimson, cardinal, ruby, vermillion and candy apple.

But it's an indisputable truth that most of these bottlings, including newly imported legacy European releases and newer American-born expressions, are standing on the shoulders of Campari, the long-reigning commendatore of red bitters. To earn a place on the backbar, they have to bring something unique to the mixing glass.