Beer style is a term used to differentiate and categorize beers by factors such as colour, flavour, strength, ingredients, production method, recipe, history, or origin.
The modern concept of beer style is largely based on the work of writer Michael Jackson in his 1977 book The World Guide To Beer in which he categorised beers from around the world into style groups according to local customs and names. In 1989, Fred Eckhardt furthered Jackson's work publishing The Essentials of Beer Style. Although the systematic study of beer styles is a modern phenomenon, the practice of distinguishing between different varieties of beer is ancient, dating to at least 2000 BC.
An alcoholic beverage is a drink that contains ethanol. Alcoholic beverages are divided into three general classes for taxation and regulation of production: beers, wines, and spirits (distilled beverages). They are legally consumed in most countries around the world. More than 100 countries have laws regulating their production, sale, and consumption. Beer is the third most popular drink in the world, after water and tea.
Alcoholic beverages have been consumed by humans since the Neolithic era; the earliest evidence of alcohol was discovered in Jiahu, dating from 7000–6600 BC. The production and consumption of alcohol occurs in most cultures of the world, from hunter-gatherer peoples to nation-states.