Brewing is the production of beer through steeping a starch source (commonly cereal grains) in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BC, and archeological evidence suggests that this technique was used in ancient Egypt. Descriptions of various beer recipes can be found in Sumerian writings, some of the oldest known writing of any sort. Brewing takes place in a brewery by a brewer, and the brewing industry is part of most western economies.
The basic ingredients of beer are water; a starch source, such as malted barley, which is able to be fermented (converted into alcohol); a brewer's yeast to produce the fermentation; and a flavouring such as hops. A secondary starch source (an adjunct) may be used, such as maize (corn), rice or sugar. Less widely used starch sources include millet, sorghum and cassava root in Africa, potato in Brazil, and agave in Mexico, among others. The amount of each starch source in a beer recipe is collectively called the grain bill.
There are several steps in the brewing process, which include malting, milling, mashing,lautering, boiling, fermenting, conditioning, filtering, and packaging. There are three main fermentation methods, warm, cool and wild or spontaneous. Fermentation may take place in open or closed vessels. There may be a secondary fermentation which can take place in the brewery, in the cask or in the bottle.
Brewing specifically refers to the process of steeping, such as with making tea, sake and soy sauce. Wine and cider technically aren't brewed, rather vinted, as the entire fruit is pressed, and then the liquid extracted. Mead isn't technically brewed, as the honey is used entirely, as opposed to being steeped in water.
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 flavoring such as hops. A mixture of starch sources may be used, with a secondary starch source, such as maize (corn), rice or 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, andagave in Mexico, among others. The amount of each starch source in a beer recipe is collectively called the grain bill.
Beer is composed mostly of water. Regions have water with different mineral components; as a result, different regions were originally better suited to making certain types of beer, thus giving them a regional character. For example, Dublin has hard water well suited to making stout, such as Guinness; while Pilsen has soft water well suited to making pale lager, such as Pilsner Urquell. The waters of Burton in England contain gypsum, which benefits making pale ale to such a degree that brewers of pale ales will add gypsum to the local water in a process known as Burtonisation.
The starch source in a beer provides the fermentable material and is a key determinant of the strength and flavour of the beer. The most common starch source used in beer is malted grain. Grain is malted by soaking it in water, allowing it to begin germination, and then drying the partially germinated grain in a kiln. Malting grain produces enzymes that convert starches in the grain into fermentable sugars. Different roasting times and temperatures are used to produce different colours of malt from the same grain. Darker malts will produce darker beers.
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 ofamylase, 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 people who cannot digest gluten-containing grains like wheat, barley, and rye.
Flavouring beer is the sole major commercial use of hops. The flower of the hop bine is used as a flavouring and preservative agent in nearly all beer made today. The flowers themselves are often called "hops". Hop cone in a Hallertau, Germany, hop yard 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 was 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 asgruit 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. They contribute a bitterness that balances the sweetness of the malt; the bitterness of beers is measured on the International Bitterness Units scale. Hops contribute floral, citrus, and herbal aromas and flavours to beer. They also have an antibiotic effect that favours the activity of brewer's yeast over less desirable microorganisms, and hops aids in "head retention", the length of time that a foamy head created by carbonation will last. The acidity of hops is a preservative.
Yeast is the microorganism that is responsible for fermentation in beer. Yeast metabolises the sugars extracted from grains, which produces alcohol and carbon dioxide, and thereby turns wort into beer. In addition to fermenting the beer, yeast influences the character and flavour. The dominant types of yeast used to make beer are ale yeast (Saccharomyces cerevisiae) and lager yeast (Saccharomyces uvarum); their use distinguishes ale and lager. Brettanomyces ferments lambics, and Torulaspora delbrueckiiferments Bavarian weissbier. Before the role of yeast in fermentation was understood, fermentation involved wild or airborne yeasts. A few styles such as lambics rely on this method today, but most modern fermentation adds pure yeast cultures.
Some brewers add one or more clarifying agents to beer, which typically precipitate (collect as a solid) out of the beer along with protein solids and are found only in trace amounts in the finished product. This process makes the beer appear bright and clean, rather than the cloudy appearance of ethnic and older styles of beer such as wheat beers.
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", it was generally clarified either with seaweed or with artificial agents, although the Fast Cask method invented by Marston's in 2009 may provide another method.
The Brewing Process
All beers are brewed using a process based on a simple formula. Key to the process is malted grain— mainly barley, though other cereals, such as wheat or rice, may be added. Malt is made by allowing a grain to germinate, after which it is then dried in a kiln and sometimes roasted. The germination process creates a number of enzymes, notably α-amylase and β-amylase, which convert the starch in the grain into sugar. Depending on the amount of roasting, the malt will take on a dark colour and strongly influence the colour and flavour of the beer. The malt is crushed to break apart the grain kernels, expose the cotyledon which contains the majority of the carbohydrates and sugars, increase their surface area, and separate the smaller pieces from the husks.