Beer style is a term used to differentiate and categorize beers by various factors including appearance, flavour, ingredients, production method, history, or origin. The term "beer style" and the structuring of world beers into defined categories is largely based on the work done by writer Michael Jackson in his 1977 book The World Guide To Beer.[1] Fred Eckhardt furthered Jackson's work publishing The Essentials of Beer Style in 1989.
There is no universally agreed list of beer styles as different countries and organisations have different sets of criteria. Organisers of beer competitions such as CAMRA's Champion Beer of Britain, the Beer Judge Certification Program's local homebrewing competitions, the Brewers Association's World Beer Cup, and the Brewing Industry International Awards have categories in which beers are judged. The categories are varied and include: "Cask Conditioned Ale",[2] Gluten Free Beer[3] and Spice, Herb, or Vegetable Beer.[4]
A number of ethnic beers, such as Chhaang and Cauim are not included on any of the main beer style groupings.
Some beer terms such as ale, lager, cask ale cover a wide variety of beer styles.