You cantor at least you shouldntmake an Old Fashioned without them! Angostura Bitters are the most famous and prevalent type of bitters. But what are bitters exactly? They are an alcoholic, highly concentrated, botanical concoction used to give your cocktail a bitter, sour, or bittersweet flavor. Because of the strong flavor bitters are added to drinks in dashes. (Two or three should do the trick.) This specific brand is named after Angostura, the Venezuelan town where they were first produced. The recipe is a closely guarded secret, with just five people knowing the exact formula. Angostura bitters were first used to soothe soldiers upset stomachs and are believed to have other healing benefits but were pretty sure your bottle will spend more time on your bar cart than in your medicine cabinet.