First, a fun graphic.
Then, the question: Does beer style matter? Asked and answered by a few members of the British Guild of Beer Writers at their annual seminar, chewed-upped, discussed to death, and then posted on various blogs (Appelation Beer, Pencil and Spoon, A Good Beer Blog, Called to the Bar). The simple OMG Beer! answer is yes. But, why does it matter?
The use of beer style as a phrase started with Michael Jackson, sort of the godfather of beer writers, and certainly a huge figure in the world of craft beer. Many styles were practically resurrected by his travels and historical research. And that's all the background you need. This phrase arises out of the movement to understand beer's history. The best definition of style I can whip up without referencing other sources (intentionally) is that "Style" refers to a range of characteristics beer possesses, and how that range in each stylistic instance gives a historical character to the beer in your hand. Levels of bitterness, specific ingredient uses, specific flavors, fall into these ranges. If I say I'm brewing a beer in the India Pale Ale style, it tells you what you can expect as far as color, bitterness, sweetness, hints at hops used, and alcohol content. It serves as a guide to both the brewer and the drinker. This alone would make the concept of style useful. On top of that guidance, style concepts help reviewers, marketers, chefs, and others.
A lot of the detractors to the modern concept of beer style argue that it is limiting, or beer should be thought of in terms of quality, not what does so and so style name say about the beer. Why should a beer be reviewed and that review influenced because there's more hop flavor than the style calls for, or a flavor considered not a part of the style's usual profile? If it tastes delicious, why knock off a point because it's lighter than the style in body or color? I feel then, we're arguing about two different things. The system of reviewing beers based on style is what you are against, not the concept of style. If your problem is that the style name doesn't explain anything to anyone but those already knowledgeable about beer history, you have a great point. That said, even a new beer drinker might recognize that naming your beer might help some people understand what to expect from it. Dark beer drinkers don't want your orange colored IPA and hopheads want to know they're buying a hoppy beer, not a chocolate and coffee flavored black hole of a pint glass. Labelling becomes more complicated and arguably more expensive, if you cut out style names and just try to find space on a simple label for the flavors evoked by your fermented concoction.
When I write out the basic thoughts above, I start to feel like the concept of beer styles has benefits, albeit ones that should be tempered by the simple idea that if beer tastes good, then it is by default, a good beer. No OMG Beer! rating will ever be reduced because there's a non-style flavor, color, hop usage, and so on. It might be noted that the true lover of X style won't like the beer as much because of an off-style use. This is useful for both the long time beer lover and the new beer drinker who wants to learn about the beverage.
There's probably more to be said about beer style, and the debate certainly will never end, especially as more and more breweries are brewing away from style, with a level of innovation no descriptive system can begin to incorporate into itself. Does rye malt and thai palm sugar and Summit hops fit into a style category? Not that I know of. Does calling Two Brothers' Cane & Ebel a rye beer (as Beer Advocate does) explain anything about it beyond the use of one ingredient? Definitely not. Is the beer delicious? Most certainly. Is "rye beer" a useful style category? No, because it could be made with rye and sweet, made with rye and bitter, made with rye and malty, made with rye and still a hop bomb, made with rye and blacker than your least favorite politician's soul, made with rye and as gold as the sun. Do we need this debate? Maybe...because I'm all for getting rid of useless style names and just keeping the ones that help us understand beer.