What is the purpose of small amounts of bitters in cocktails? For example, 1/32nd tsp angostura bitters in a Manhattan? Do they provide any function other than flavor, such as binding, texture, or mysterious chemical reaction?
1Can you narrow down what you mean by bitters? Are you talking about the kind that is measured in "dashes" like Angostura, or Orange Bitters? Or perhaps something more (volumetrically) dominating like Campari, Fernet, or other Amari? Jaegermeister is even referred to as a bitter.– RayJun 14, 2012 at 3:06
I've edited the question - hopefully that helps! I didn't even know there were other things in the "bitters" category.– KatieKJun 14, 2012 at 3:14
Bitters originally were supposed to have medicinal properties, which is why some still have "tonic" in their names. Now they're just a flavoring agent, a concentrated way to enrich the cocktail and bring out more subtle flavor notes.
Given how little bitters you put in most drinks, it's unlikely they alter mouthfeel or other qualities much.