All bitters are aromatic, right? Why else would you use them if not to bring aroma (on a foundation of bitterness) to your drink? "Aromatic Bitters" refers to the family of bitters that are composite, cohesive wholes. Citrus bitters may taste like orange or yuzu. Aromatic bitters taste like "I want you in my drink!" They're the foundation of an Old Fashioned, indispensable in a Manhattan, and wonderful in all manner of whiskey, rum, dark tequila, and even many rum drinks.