Beer style is a term used to differentiate and categorize beers by various factors, including appearance, flavour, ingredients, production method, history, or origin.
[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.
The categories are varied and include processes or ingredients not usually regarded as defining beer styles in themselves, such as cask ale or gluten-free beer.
Beers that originated in a particular country or region may be subsequently produced in other countries, e.g. British style ales are now brewed in North America.