A beer style describes a cluster of beers, with common features that make them similar, while distinguishing them from all others.  These differences may relate to ingredients, brewing method, fermentation, conditioning, strength, or in a few cases, the way they are served.  Put another way ….

Some beer styles have been around for centuries, while others come from a moment of inspiration or calculation by a particular brewer that impacted so much that others knew they needed to follow. 

Describing beer styles enables competitions to award prizes to the brewers who make the best, provoking others to go one step better.  It also aids discussion about different types of beer and helps with spotting those breweries that always seem to be good performers.

For both brewers and consumers, being able to talk about beer styles improves the quality of information and encourages diversity over uniformity.