When describing styles of beer, vital statistics such as final gravity, color, alcohol, and IBU provide the terminology framework in which to describe beer in the sensory terms of: residual sweetness, maltiness, alcohol, and bitterness respectively. With this new wave of styles containing widely varying flavor profiles, it’s necessary to start using terms to describe the vast world of lost beers simply deemed “Sours” by many. In order for these new styles to get individual recognition, the marketplace first needs to build the vocabulary to describe them. Consumers are struggling to memorize the difference between new elements such as lactic acid (softer sour) and acetic acid (vinegar sour) that weren’t part of their beer description vocabularies before. Where previously a popcorn smell was immediately blamed on diacetyl, the modern wild ale judge must distinguish between the slick artificial buttery flavor of diacetyl and the cereal grainy characteristic of tetrahydropyridine (THP.) Some find THP to be rather pleasant in small quantities, while most people despise diacetyl in all its forms. Confusing the two can ruin a beer description and really piss off brewers.
Brendan Megowan, “Wild Style”, Beer Paper LA (July 2016), 19.