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 cereals — the most common of which is malted barley, although wheat, corn, and rice are also 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. Alcoholic beverages fermented from non-starch sources such as grape juice (wine) or honey (mead) or distilled after fermentation are not classified as beer.
Some of mankind'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 huge 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, and are commonly categorised into two main types — 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 may range from less than 1% abv (alcohol by volume) to over 20% abv in rare cases, though is usually around 4% to 6% abv.
Beer forms part of the culture of various beer drinking nations, and has acquired various social traditions and associations, such as beer festivals and a rich pub culture involving activities such as pub crawling or pub games such as bar billiards.
Beer is one of the world's oldest beverages, possibly dating back to the 6th millennium BC, and is recorded in the written history of ancient Egypt and Mesopotamia. The earliest Sumerian writings contain references to 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.
As almost any substance containing carbohydrates, mainly sugar 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 3500–3100 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, though was mainly brewed on a domestic scale. Though the product that the early European would have been drinking might not always be recognised as beer by most people today. The early European beers might contain alongside the basic starch source: fruits, honey, numerous types of plants, spices and other sustances such as narcotic drugs. 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. More than 133 billion liters (35 billion gallons) are sold per year—producing total global revenues of $294.5 billion (£147.7 billion) in 2006.
The purpose of brewing is to convert the starch source into a sugary liquid called wort which is then able to be fermented by yeast into the alcoholic beverage known as beer. The first step, where the wort is created by mixing the starch source (normally malted barley) with hot water, is known as "mashing". Hot water (known as "liquor" in brewing terms) is mixed with crushed malt or malts (known as the "grain bill") in a mash tun. The mashing process takes around 1 to 2 hours, during which the starches are converted to sugars, and then the sweet wort is drained off the grains. The grains are now washed in a process known as "sparging" or "lautering". This washing allows the brewer to gather as much of the fermentable liquid from the grains as possible. Most modern breweries use a continuous wash. However, it is possible to go through a second or even third mash with the not quite spent grains. Each run would produce a weaker wort and thus a weaker beer. This process is known as second (and third) runnings. To brew with several runnings is called parti gyle brewing.
The sweet wort collected from sparging is put into a kettle or "copper" (so called because these vessels were traditionally made from copper) and boiled, usually for about one hour. During boiling, water in the wort evaporates, but the sugars and other components of the wort remain; this allows more efficient use of the starch sources in the beer. Boiling also destroys any remaining enzymes left over from the mashing stage. Hops are added during boiling in order to extract bitterness, flavour and aroma from them. Hops may be added at more than one point during the boil. The longer the hops are boiled, the more bitterness they contribute but less of the hop flavour and aroma remains in the beer.
After boiling, the hopped wort is now cooled ready for the yeast. In some breweries the hopped wort may pass through a "hopback" which is a small vat filled with hops, to add aromatic hop flavouring, and also to act as a filter; but usually the hopped wort is simply cooled for the fermenter, where the yeast is added. During fermentation, the wort becomes beer in a process which requires a week to months depending on the type of yeast and strength of the beer. In addition to producing alcohol, fine particulate matter suspended in the wort settles during fermentation. Once fermentation is complete, the yeast also settles, leaving the beer clear.
Fermentation is sometimes carried out in two stages, primary and secondary. Once most of the alcohol has been produced during primary fermentation, the beer is transferred to a new vessel and allowed a period of secondary fermentation. Secondary fermentation is used when the beer requires long storage before packaging or greater clarity. When the beer has fermented it is packaged either into casks for cask ale or kegs or bottles for other sorts of beer.
The basic ingredients of beer are water; a starch source, such as malted barley, able to be fermented (converted into alcohol); a brewer's yeast to produce the fermentation; and a flavouring such as hops. A mixture of starch sources may be used, with a secondary starch source, such as corn, rice and sugar, often being termed an adjunct, especially when used as a lower cost substitute for malted barley. Less widely used starch sources include millet, sorghum and cassava root in Africa, potato in Brazil, and agave in Mexico, among others.
Nearly all beer includes barley malt as the majority of the starch. This is because of its fibrous husk, which is not only important in the sparging stage of brewing (in which water is washed over the mashed barley grains to form the wort), but also as a rich source of amylase, a digestive enzyme which facilitates conversion of starch into sugars. Other malted and unmalted grains (including wheat, rice, oats, and rye, and less frequently, corn and sorghum) may be used. In recent years a few brewers have produced gluten-free beer made with sorghum with no barley malt for those who cannot consume gluten-containing grains like wheat, barley, and rye.
The use of hops in beer was recorded by captive Jews in Babylon around 400 BC. Hops were used by monastery breweries, such as Corvey in Westphalia, Germany, from 822 AD, though the date normally given for widespread cultivation of hops for use in beer is the thirteenth century. Before the thirteenth century, and until the sixteenth century during which hops took over as the dominant flavouring, beer would be flavoured with other plants; for instance, Glechoma hederacea. Combinations of various aromatic herbs, berries, and even ingredients like wormwood would be combined into a mixture known as gruit and used as hops are now used. Some beers today, such as Fraoch by the Scottish Heather Ales company, and Cervoise Lancelot by the French Brasserie-Lancelot company, use plants other than hops for flavouring.
Hops contain several characteristics that brewers desire in beer: hops contribute a bitterness that balances the sweetness of the malt;The bitterness of beers is measured on the International Bitterness Units scale. Hops also contribute floral, citrus, and herbal aromas and flavours to beer; hops have an antibiotic effect that favours the activity of brewer's yeast over less desirable microorganisms; and the use of hops aids in "head retention", the length of time that a foamy head created by carbonation will last. The acidity of hops acts as a preservative.
Common examples of clarifying agents include isinglass, obtained from swimbladders of fish; Irish moss, a seaweed; kappa carrageenan, from the seaweed Kappaphycus cottonii; Polyclar (artificial); and gelatin. If a beer is marked 'suitable for Vegans' then it has either been clarified with seaweed or with artificial agents.
While there are many different brands of beer brewed around the globe, the basics of brewing beer are shared across national and cultural boundaries. The traditional European brewing regions — Germany, Belgium, the United Kingdom, Ireland, Poland, the Czech Republic, Denmark, The Netherlands and Austria — have local varieties of beer. In some countries, notably the USA, Canada and Australia, brewers have adapted European styles to such an extent that they have effectively created their own indigenous types. Despite the regional variations, beer is commonly categorised into two main types — the globally popular pale lagers and the more regionally distinct ales which are further categorised into other varieties such as pale ale, stout and brown ale.
The late British beer writer Michael Jackson in his 1977 book The World Guide To Beer categorised a variety of beers from around the world in local style groups suggested by local customs and names. Fred Eckhardt furthered Jackson's work in The Essentials of Beer Style in 1989. These books had an influence on homebrewers in United States who developed an intricate system of categorising beers which is exemplified by the Beer Judge Certification Program.
The most common method of categorising beer is by the behaviour of the yeast used in the fermentation process. In this method of categorising, beers using a fast-acting yeast, which leaves behind residual sugars, are termed "ales", while beers using a slower-acting yeast, fermented at lower temperatures, which removes most of the sugars and leaving a clean, dry beer, are termed "lagers". Differences between some ales and lagers can be difficult to categorise. Steam beer, Kölsch, Alt, and some modern British Golden Summer Beers use elements of both lager and ale production. Baltic Porter and Bière de Garde may be produced by either lager or ale methods or a combination of both. However, lager production results in a cleaner tasting, drier and lighter beer than ale.
A modern ale is commonly defined by the strain of yeast used and the fermenting temperature. Ales are normally brewed with top-fermenting yeasts (most commonly Saccharomyces cerevisiae), though a number of British brewers, including Fullers and Weltons, use ale yeast strains that have less pronounced top-fermentation characteristics. The important distinction for ales is that they are fermented at higher temperatures and thus ferment more quickly than lagers. Ale is typically fermented at temperatures between 15 and 24 °C (60 and 75 °F). At these temperatures, yeast produces significant amounts of esters and other secondary flavour and aroma products, and the result is often a beer with slightly "fruity" compounds resembling apple, pear, pineapple, banana, plum, or prune, among others. Typically ales have a sweeter, fuller body than lagers.
Before the introduction of hops into England from the Netherlands in the 15th century the name "ale" was exclusively applied to unhopped fermented beverages, the term "beer" being gradually introduced to describe a brew with an infusion of hops. This distinction no longer applies. The word 'ale' may come from the Old English ealu, in turn from the Proto-Indo-European base *alut-, which holds connotations of "sorcery, magic, possession, intoxication".
Real ale is the term coined by the Campaign for Real Ale (CAMRA) in 1973 for "beer brewed from traditional ingredients, matured by secondary fermentation in the container from which it is dispensed, and served without the use of extraneous carbon dioxide". It is applied both to bottle conditioned and cask conditioned beers.
Lambic, a beer of Belgium, is naturally fermented using wild yeasts, rather than cultivated. Many of these are not strains of brewer's yeast (Saccharomyces cerevisiae), and may have significant differences in aroma and sourness. Yeast varieties such as Brettanomyces bruxellensis and Brettanomyces lambicus are quite common in lambics. In addition, other organisms such as Lactobacillus bacteria produce acids which contribute to the sourness.
Lager is the English name for cool fermenting beers of Central European origin. Pale lagers are the most commonly consumed beers in the world. The name "lager" comes from the German lagern for "to store", as brewers around Bavaria stored beer in cool cellars and caves during the warm summer months. These brewers noticed that the beers continued to ferment, and also to clear of sediment when stored in cool conditions.
Lager yeast is a cool "bottom-fermenting yeast" (Saccharomyces pastorianus), and typically undergoes primary fermentation at 7–12 °C (45–55 °F) (the "fermentation phase"), and then is given a long secondary fermentation at 0–4 °C (32–40 °F) (the "lagering phase"). During the secondary stage, the lager clears and mellows. The cooler conditions also inhibit the natural production of esters and other byproducts, resulting in a "cleaner" tasting beer.
Modern methods of producing lager were pioneered by Gabriel Sedlmayr the Younger, who perfected dark brown lagers at the Spaten Brewery in Bavaria, and Anton Dreher, who began brewing a lager, probably of amber-red colour, in Vienna in 1840–1841. With improved modern yeast strains, most lager breweries use only short periods of cold storage, typically 1–3 weeks.
The colour of a beer is determined by the malt. The most common colour is a pale amber produced from using pale malts. "Pale lager" and "pale ale" are terms used for beers made from malt dried with coke. Coke had been first used for roasting malt in 1642, but it was not until around 1703 that the term "pale ale" was first used.
In terms of sales volume, most of today's beer is based on the pale lager brewed in 1842 in the town of Pilsen, in the Czech Republic. The modern pale lager is light in colour with a noticeable carbonation (fizzy bubbles), and a typical alcohol by volume content of around 5%. The Pilsner Urquell, Bitburger, and Heineken brands of beer are typical examples of pale lager, as are the American brands Budweiser, Coors, and Miller.
Dark beers are usually brewed from a pale malt or lager malt base with a small proportion of darker malt added to achieve the desired shade. Other colourants—such as caramel—are also widely used to darken beers. Very dark beers, such as stout use dark or patent malts that have been roasted longer. Guinness and similar beers include roasted unmalted barley.
The alcohol in beer comes primarily from the metabolism of sugars that are produced during fermentation. The quantity of fermentable sugars in the wort and the variety of yeast used to ferment the wort are the primary factors that determine the amount of alcohol in the final beer. Additional fermentable sugars are sometimes added to increase alcohol content, and enzymes are often added to the wort for certain styles of beer (primarily "light" beers) to convert more complex carbohydrates (starches) to fermentable sugars. Alcohol is a byproduct of yeast metabolism and is toxic to the yeast; typical brewing yeast cannot survive at alcohol concentrations above 12% by volume. Low temperatures and too little fermentation time decreases the effectiveness of yeasts, and consequently decreases the alcohol content.
Since then some brewers have used champagne yeasts to increase the alcohol content of their beers. Samuel Adams reached 20% abv with Millennium and then surpassed that amount to 25.6% abv with Utopias. The strongest beer sold in Britain was Delaware's Dogfish Head's World Wide Stout, a 21% abv stout which was available from UK Safeways in 2003. In Japan in 2005, the Hakusekikan Beer Restaurant sold an eisbock, strengthened through freeze distillation, believed to be 28% abv. The beer that is considered to be the strongest yet made is Hair of the Dog's Dave—a 29% abv barley wine made in 1994. The strength was achieved by freeze distilling a 10% ale twice.
SABMiller became the largest brewing company in the world when it acquired Royal Grolsch, Brewer of Dutch premium beer brand Grolsch. InBev is the second-largest beer-producing company in the world, and Anheuser-Busch holds the third spot, but after the proposed merger (announced 13 July 2008), between InBev and Anheuser-Busch, the new Anheuser-Busch InBev company will be the largest brewer in the world.
Draught beer from a pressurised keg is the most common method of dispensing in bars around the world. A metal keg is pressurised with carbon dioxide (CO2) gas which drives the beer to the dispensing tap or faucet. Some beers, notably stouts, such as Guinness and "smooth" bitters, such as Boddingtons, may be served with a nitrogen/carbon dioxide mixture. Nitrogen produces fine bubbles, resulting in a dense head and a creamy mouthfeel. Some types of beer can also be found in smaller, disposable kegs called beer balls.
In the 1980s, Guinness introduced the beer widget, a nitrogen pressurised ball inside a can which creates a foamy head. The words "draft" and "draught" can be used as marketing terms to describe canned or bottled beers containing a beer widget, or which are cold filtered rather than pasteurised.
Cask-conditioned ales (or "cask ales") are unfiltered and unpasteurised beers. These beers are termed "real ale" by the CAMRA organisation. Typically, when a cask arrives in a pub, it is placed horizontally on a frame called a "stillage" which is designed to hold it steady and at the right angle, and then allowed to cool to cellar temperature (typically between 12-14 °C/53-57 °F), before being tapped and vented—a tap is driven through a (usually rubber) bung at the bottom of one end, and a hard spile or other implement is used to open a hole in the side of the cask, which is now uppermost. The act of stillaging and then venting a beer in this manner typically disturbs all the sediment, so it must be left for a suitable period to "drop" (clear) again, as well as to fully condition—this period can take anywhere from several hours to several days. At this point the beer is ready to sell, either being pulled through a beer line with a hand pump, or simply being "gravity-fed" directly into the glass.
Most beers are cleared of yeast by filtering when packaged in bottles and cans. However, bottle conditioned beers retain some yeast—either by being unfiltered, or by being filtered and then reseeded with fresh yeast. It is usually recommended that the beer be poured slowly, leaving any yeast sediment at the bottom of the bottle. However, some drinkers prefer to pour in the yeast; this practice is customary with wheat beers. Typically, when serving a hefeweizen, 90% of the contents are poured, and the remainder is swirled to suspend the sediment before pouring it into the glass. Alternatively, the bottle may be inverted prior to opening. Glass bottles are always used for bottle conditioned beers.
Many beers are sold in beverage cans, though there is considerable variation in the proportion between different countries. In 2001, in Sweden 63.9% of beer was sold in cans. People either drink from the can or pour the beer into a glass. Cans protect the beer from light and have a seal less prone to leaking over time than bottles. Cans were initially viewed as a technological breakthrough for maintaining the quality of a beer, then became commonly associated with less-expensive, mass-produced beers, even though the quality of storage in cans is much like bottles. Plastic (PET) bottles are used by some breweries.
Beer writer Michael Jackson proposed a five-level scale for serving temperatures: well chilled (7 °C/45 °F) for "light" beers (pale lagers); chilled (8 °C/47 °F) for Berliner Weisse and other wheat beers; lightly chilled (9 °C/48 °F) for all dark lagers, altbier and German wheat beers; cellar temperature (13 °C/55 °F) for regular British ale, stout and most Belgian specialities; and room temperature (15.5 °C/60 °F) for strong dark ales (especially trappist beer) and barley wine.
Drinking chilled beer is a social trend that began with the development of artificial refrigeration, and by the 1870s was spread in those countries that concentrated on brewing pale lager. Chilling below 15.5 °C/60 °F starts to reduce taste awareness, and reduces it significantly below 10 °C/50 °F; while this is acceptable for beers without an appreciable aroma or taste profile, beers brewed with more than basic refreshment in mind reveal their flavours more when served unchilled - either cool or at room temperature. Cask Marque, a non profit making UK beer organisation, has set a temperature standard range of 12°-14°C (53°-57°F) for cask ales to be served.
The pouring process has an influence on a beer's presentation. The rate of flow from the tap or other serving vessel, tilt of the glass, and position of the pour (in the centre or down the side) into the glass all influence the end result, such as the size and longevity of the head, lacing (the pattern left by the head as it moves down the glass as the beer is drunk), and turbulence of the beer and its release of carbonation.
Brewer's yeast is known to be a rich source of nutrients; therefore, as expected, beer can contain significant amounts of nutrients, including magnesium, selenium, potassium, phosphorus, biotin, and B vitamins. In fact, beer is sometimes referred to as "liquid bread". Some sources maintain that filtered beer loses much of its nutrition.
A 2005 Japanese study found that low alcohol beer may possess strong anti-cancer properties. Another study found nonalcoholic beer to mirror the cardiovascular benefits associated with moderate consumption of alcoholic beverages. However, much research suggests that the primary health benefit from alcoholic beverages comes from the alcohol they contain.
It is considered that overeating and lack of muscle tone is the main cause of a beer belly, rather than beer consumption. A recent study, however, found a link between binge drinking and a beer belly. But with most overconsumption it is more a problem of improper exercise and overconsumption of carbohydrates than the product itself. Several diet books quote beer as having the same glycemic index as maltose, a very high (and therefore undesirable) 110; however the maltose undergoes metabolism by yeast during fermentation so that beer consists mostly of water, hop oils and only trace amounts of sugars, including maltose.