These days, there seem to be more hopheads out there than uhh....human heads. And yet, not many people know what exactly goes into their bitter beers—what makes each brew different from the other. Hoppiness exists not merely as a linear scale of IBUs, but as an array of flavors, aromas, and bitterness. Each hop variety (and there are dozens) is different, and identifying them is easier than you might think. Let's start with the hope you're most likely to be sipping in your pint of American IPA: a group of hops known as the "Three C's."