Beer is the world's oldest and most widely consumed alcoholic beverage and the third most popular drink overall after water and tea. It is produced by the brewing and fermentation of starches, mainly derived from cereal grainsâ€”most commonly malted barley, although wheat, maize (corn), and rice are widely used. Most beer is flavoured with hops, which add bitterness and act as a natural preservative, though other flavourings such as herbs or fruit may occasionally be included.
Some of humanity's earliest known writings refer to the production and distribution of beer: the Code of Hammurabi included laws regulating beer and beer parlours, and ``The Hymn to Ninkasi,`` a prayer to the Mesopotamian goddess of beer, served as both a prayer and as a method of remembering the recipe for beer in a culture with few literate people. Today, the brewing industry is a global business, consisting of several dominant multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries.
The basics of brewing beer are shared across national and cultural boundaries. Beers are commonly categorized into two main typesâ€”the globally popular pale lagers, and the regionally distinct ales, which are further categorised into other varieties such as pale ale, stout and brown ale. The strength of beer is usually around 4% to 6% alcohol by volume (abv.) though may range from less than 1% abv., to over 20% abv. in rare cases.
Beer forms part of the culture of beer-drinking nations and is associated with social traditions such as beer festivals, as well as a rich pub culture involving activities like pub crawling and pub games such as bar billiards.
Beer is one of the world's oldest prepared beverages, possibly dating back to the early Neolithic or 9000 BC, and is recorded in the written history of ancient Egypt and Mesopotamia. The earliest Sumerian writings contain references to a type of beer. A prayer to the goddess Ninkasi, known as ``The Hymn to Ninkasi``, serves as both a prayer as well as a method of remembering the recipe for beer in a culture with few literate people. A beer made from rice, which, unlike sake, didn't use the amylolytic process, and was probably prepared for fementation by mastication or malting, was made in China around 7,000 BC.
As almost any substance containing carbohydrates, mainly sugars or starch, can naturally undergo fermentation, it is likely that beer-like beverages were independently invented among various cultures throughout the world. The invention of bread and beer has been argued to be responsible for humanity's ability to develop technology and build civilization. The earliest known chemical evidence of beer dates to circa 3500â€“3100 BC from the site of Godin Tepe in the Zagros Mountains of western Iran.
Beer was spread through Europe by Germanic and Celtic tribes as far back as 3000 BC, and it was mainly brewed on a domestic scale. The product that the early Europeans drank might not be recognised as beer by most people today. Alongside the basic starch source, the early European beers might contain fruits, honey, numerous types of plants, spices and other substances such as narcotic herbs. What they did not contain was hops, as that was a later addition first mentioned in Europe around 822 by a Carolingian Abbot and again in 1067 by Abbess Hildegard of Bingen.
Beer produced before the Industrial Revolution continued to be made and sold on a domestic scale, although by the 7th century AD, beer was also being produced and sold by European monasteries. During the Industrial Revolution, the production of beer moved from artisanal manufacture to industrial manufacture, and domestic manufacture ceased to be significant by the end of the 19th century. The development of hydrometers and thermometers changed brewing by allowing the brewer more control of the process and greater knowledge of the results.
Today, the brewing industry is a global business, consisting of several dominant multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries. As of 2006, more than 133 billion liters (35 billion gallons), the equivalent of a cube 510 metres on a side, of beer are sold per year, producing total global revenues of $294.5 billion (Â£147.7 billion).
The process of making beer is known as brewing. A dedicated building for the making of beer is called a brewery, though beer can be made in the home and has been for much of its history. A company that makes beer is called either a brewery or a brewing company. Beer made on a domestic scale for non-commercial reasons is classed as homebrewing regardless of where it is made, though most homebrewed beer is made in the home. Brewing beer is subject to legislation and taxation in developed countries, which from the late 19th century largely restricted brewing to a commercial operation only. However, the UK government relaxed legislation in 1963, followed by Australia in 1972 and the USA in 1979, allowing homebrewing to become a popular hobby.