Beer is the world’s most widely consumed alcoholic beverage; it is the third-most popular drink overall, after water and tea. It is thought by some to be the oldest fermented beverage. Beer is produced by the saccharification of starch and fermentation of the resulting sugar. The starch and saccharification enzymes are often derived from malted cereal grains, most commonly malted barley and malted wheat. Unmalted maize and rice are widely used adjuncts to lighten the flavor because of their lower cost. The preparation of beer is called brewing. 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.
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 strength of beer is usually around 4% to 6% alcohol by volume (abv) although it may vary between 0.5% (de-alcoholized) and 20%, with some breweries creating examples of 40% abv and above in recent years.
The beer types are classified as bottom-fermented and top-fermented, depending on the strain of yeast used:
Bottom-fermented beer types are obtained by fermenting with “bottom” strains. The yeast is deposited as a layer at the bottom of the fermentation vessel, so allowing the beer to ferment only slowly. German purity regulations allow bottom-fermented beer to be made solely from barley malt, hops, yeast and water. The following are examples of bottom-fermented types:
Top-fermented beer types are fermented rapidly by top strains which rise to the surface. Top-fermented beer may have other types of malt and sugar added to it, in addition to the basic ingredients.
Beer differs in color depending on type, ranging from light yellow to dark brown. Haziness of the beer may be caused by excessively long, cold storage and yeast residues. Flavor impairment may result from incorrectly sealed containers.
Maximum duration of storage depends principally on type of packaging and beer type.
Canned beer has the longest shelf-life, but it may take on a slightly metallic taste if stored for an extended period.
Bottled beer should be consumed within three months at the most, as its flavor and color may be impaired during storage by the action of oxygen.
Draft beers have the shortest storage life. They should be consumed within a maximum of one month.
Bottom-fermented types have a longer storage life than top-fermented types.
The basic ingredients of beer are water; a starch source, such as malted barley, able to be saccharified (converted to sugars) then fermented (converted into alcohol and carbon dioxide); 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 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, and 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.
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 Plzeň 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 its fibrous hull remains attached to the grain during threshing. After malting, barley is milled, which finally removes the hull, breaking it into large pieces. These pieces remain with the grain during the mash, and act as a filter bed during lautering, when sweet wort is separated from insoluble grain material. 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.
Flavouring beer is the sole major commercial use of hops. The flower of the hop vine is used as a flavouring and preservative agent in nearly all beer made today. The flowers themselves are often called “hops”.
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 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 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 the top-fermenting Saccharomyces cerevisiae and bottom-fermenting Saccharomyces uvarum. Brettanomyces ferments lambics, and Torulaspora delbrueckii ferments 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 clarified either with seaweed or with artificial agents.
While there are many types of beer brewed, the basics of brewing beer are shared across national and cultural boundaries. The traditional European brewing regions—Germany, Belgium, England and the Czech Republic—have local varieties of beer.
Top-fermented beers are most commonly produced with Saccharomyces cerevisiae, a top-fermenting yeast which clumps and rises to the surface, typically 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.
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.
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 to bottle conditioned and cask conditioned beers.
Pale ale is a beer which uses a top-fermenting yeast and predominantly pale malt. It is one of the world’s major beer styles.
Stout and porter are dark beers made using roasted malts or roast barley, and typically brewed with slow fermenting yeast. There are a number of variations including Baltic porter, dry stout, and Imperial stout.
Mild ale has a predominantly malty palate. It is usually dark coloured with an abv of 3% to 3.6%, although there are lighter hued milds as well as stronger examples reaching 6% abv and higher.
Wheat beer is brewed with a large proportion of wheat although it often also contains a significant proportion of malted barley. Wheat beers are usually top-fermented (in Germany they have to be by law). The flavour of wheat beers varies considerably, depending upon the specific style.
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 to also 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 (45–54 °F) (the fermentation phase), and then is given a long secondary fermentation at 0–4 °C (32–39 °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 (now known as Vienna 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.
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 common in lambics. In addition, other organisms such as Lactobacillus bacteria produce acids which contribute to the sourness.
Beer colour 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 was first used for roasting malt in 1642, but it was not until around 1703 that the term pale ale was 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 present-day 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. Some have roasted unmalted barley.
Beer ranges from less than 3% alcohol by volume (abv) to around 14% abv, though this strength can be increased to around 20% by re-pitching with champagne yeast, and to 55% abv by the freeze-distilling process. The alcohol content of beer varies by local practice or beer style. The pale lagers that most consumers are familiar with fall in the range of 4–6%, with a typical abv of 5%. The customary strength of British ales is quite low, with many session beers being around 4% abv. Some beers, such as table beer are of such low alcohol content (1%–4%) that they are served instead of soft drinks in some schools.
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 by-product 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.
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 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 1980’s, Guinness introduced the beer widget, a nitrogen-pressurised ball inside a can which creates a dense, tight head, similar to beer served from a nitrogen system. 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 11–13 °C / 52–55 °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 wheat beer, 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 cans, though there is considerable variation in the proportion between different countries. In Sweden in 2001, 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 (thereby preventing “skunked” beer) 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.
The temperature of a beer has an influence on a drinker’s experience; warmer temperatures reveal the range of flavours in a beer but cooler temperatures are more refreshing. Most drinkers prefer pale lager to be served chilled, a low- or medium-strength pale ale to be served cool, while a strong barley wine or imperial stout to be served at room temperature.
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/46 °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/59.9 °F) for strong dark ales (especially trappist beer) and barley wine.
Beer is drunk both neat and mixed with other beverages.
Shipment / Storage
Beer is packed in containers such as drinks cans, glass bottles, plastic bottles (PET (polyethylene terephthalate)), barrels and tank containers.
Beer in returnable bottles is mainly transported in stackable plastic crates.
Beer in non-returnable bottles and cans is for the most part packed in cardboard or corrugated board boxes in groups of 6 bottles or 6 to 24 cans. The packaging size is so selected that the dimensions of the individual area modules or area module multiples are conformed to the conventional pallet sizes (800×1200 mm and 1000×1200 mm) and cargo units may thus be produced.
When beer is transported in cartons, the following markings should be visible on every side of the packaging:
Beer may be transported as general cargo in standard containers, subject to compliance with limits for water content of packaging, pallets and flooring. Beer may also be transported as liquid cargo in tank containers.
Since cans and bottles in particular are highly impact- and pressure-sensitive, appropriate care must be taken during cargo handling, to prevent damage. Dented cans constitute a clear reduction in value. Broken bottles entail the additional nuisance of contaminating other cargo.
It is also imperative that the goods be protected from moisture (rain, snow) during cargo handling and from excessively low and high temperatures. Moisture may result in detachment of labels and corrosion of crown caps and cans.
Unfavorable temperatures may cause quality degradation due to increased activity of microorganisms or haziness of the beer.
Many beers are transported bottled or canned in cases or cartons. Also transported in barrels. When shipped or otherwise transported in barrels can be very much affected by variations in, and extremes of, temperature. For bottled or canned beers losses may frequently be attributed to wetting from external causes, collapse of cartons, breakage of bottles, denting or collapse of cans, soiling of labels and corrosion. Moisture contamination to cartons can cause deterioration to the metalling on pull-top cans and if left for a period will deteriorate the metalling allowing air to enter and rendering contents a total loss. In some countries the rate of excise duty leaves little or no margin for reconditioning to be economical.
The following Table merely constitutes a rough estimate of appropriate temperature ranges. Temperatures may deviate from these values, depending on the particular transport conditions.
As the optimum temperature for beer is between approx. 3 and 8°C, it is best transported as refrigerated cargo, to inhibit the metabolic activity of the microorganisms.
At temperatures of below 2°C, chill haze occurs as a result of the precipitation of protein/tannin compounds, although this is reversible if caught early enough. If the chill haze lasts for a relatively long period, it becomes permanent and the beer becomes bitter.
At temperatures of below approx. -3°C (depending upon alcohol content), ice expansion may occur. Cargo handling in frosty conditions in winter must therefore be performed very quickly.
Beer must additionally be protected from relatively large temperature fluctuations, so as to prevent precipitation or haze. Excessively severe solar radiation may cause light flavor tainting. CO2 solubility reduces, so protection from excessive temperatures and temperature fluctuations must be provided.
Beer requires particular temperature, humidity/moisture and possibly ventilation conditions. Recommended ventilation conditions: air exchange rate: 6 changes/hour (airing), if there is a risk of the formation of cargo sweat, which may lead, for example, to label detachment.
- Excessive temperatures and temperature fluctuations cause CO2 solubility to reduce, resulting in quality degradation.
- Self-heating / Spontaneous combustion
- Mechanical influences
- Shrinkage/Shortage (Beer is at considerable risk of theft; it must therefore be ensured as early as at the point of acceptance of a consignment that the cargo is complete).
- Insect infestation / Diseases. Microbial spoilage is caused by infection of the beer at the brewery and results in haze and the formation of an unappetizing, acidic flavor.