Lager is a type of beer conditioned at low temperatures. It may be pale, golden, amber, or dark. Pale lager is the most widely consumed and commercially available style of beer. Well-known brands include Pilsner Urquell, Miller, Stella Artois, Beck's, Brahma, Budweiser Budvar, Corona, Snow, Tsingtao, Singha, Kirin, Heineken, Carling, Foster's, and Carlsberg.
As well as maturation in cold storage, lager is also distinguished by the use of the Saccharomyces pastorianus yeast. While it is possible to use lager yeast in a warm fermentation process, such as with American steam beer, the lack of a cold storage maturation phase precludes such beer from being classified as lager. On the other hand, German Altbier and Kölsch, brewed with a Saccharomyces cerevisiae top-fermenting yeast at a warm temperature, but with a cold storage finishing stage, are classified as obergäriges lagerbier (top-fermented lager beer).
Until the 19th century, the German word lagerbier (de) referred to all types of bottom-fermented, cool-conditioned beer, in normal strengths. In Germany today, however, the term is mainly reserved for the prevalent lager beer styles of southern Germany, "Helles" (pale), or a "Dunkel" (dark). Pilsner, a more heavily hopped pale lager, is most often known as "Pilsner", "Pilsener", or "Pils". Other lagers are Bock, Märzen, and Schwarzbier. In the United Kingdom, the term lager commonly refers specifically to pale lagers, many of which are derived from the Pilsner style.
While cold storage of beer, "lagering", in caves for example, was a common practice throughout the medieval period, bottom-fermenting yeast seems to have emerged as a hybridization in the early fifteenth century. In 2011, a team of researchers claimed to have discovered that Saccharomyces eubayanus is responsible for creating the hybrid yeast used to make lager.
Based on the numbers of breweries, lager brewing became the main form of brewing in Bohemia between 1860 and 1870, as shown in the following table:
|Year||Total Breweries||Lager Breweries||Lager Percentage|
In the 19th century, prior to the advent of refrigeration, German brewers would dig cellars for lagering and fill them with ice from nearby lakes and rivers, which would cool the beer during the summer months. To further protect the cellars from the summer heat, they would plant chestnut trees, which have spreading, dense canopies but shallow roots which would not intrude on the caverns. The practice of serving beer at these sites evolved into the modern beer garden.
The rise of lager was entwined with the development of refrigeration, as refrigeration made it possible to brew lager year-round (brewing in the summer had previously been banned in many locations across Germany), and efficient refrigeration also made it possible to brew lager in more places and keep it cold until serving. The first large-scale refrigerated lagering tanks were developed for Gabriel Sedelmayr's Spaten Brewery in Munich by Carl von Linde in 1870.
Lager beer uses a process of cool fermentation, followed by maturation in cold storage. The German word "Lager" means storeroom or warehouse. The yeast generally used with lager brewing is Saccharomyces pastorianus. It is a close relative of the Saccharomyces cerevisiae yeast used for warm fermented ales.
While prohibited by the German Reinheitsgebot tradition, lagers in some countries often feature large proportions of adjuncts, usually rice or maize. Adjuncts entered United States brewing as a means of thinning out the body of U.S. beers, balancing the large quantities of protein introduced by six-row barley. Adjuncts are often used now in beermaking to introduce a large quantity of sugar, and thereby increase ABV, at a lower price than a formulation using an all-malt grain bill. There are however cases in which adjunct usage actually increases the cost of manufacture.
The examples of lager beers produced worldwide vary greatly in flavor, color, composition and alcohol content.
The most common lager beers in worldwide production are pale lagers. The flavor of these lighter lagers is usually mild, and the producers often recommend that the beers be served refrigerated.
Pale lager is a very pale to golden-colored lager with a well attenuated body and noble hop bitterness. The brewing process for this beer developed in the mid 19th century when Gabriel Sedlmayr took pale ale brewing techniques back to the Spaten Brewery in Germany and applied it to existing lagering brewing methods.
This approach was picked up by other brewers, most notably Josef Groll who produced in Bohemia (now part of the Czech Republic) the first Pilsner beer—Pilsner Urquell. The resulting pale colored, lean and stable beers were very successful and gradually spread around the globe to become the most common form of beer consumed in the world today.
Distinctly amber colored Vienna lager was developed by brewer Anton Dreher in Vienna in 1841. Austrian brewers who emigrated to Mexico in the late 19th century took the style with them. Vienna lager is a reddish-brown or copper-colored beer with medium body and slight malt sweetness. The malt aroma and flavor may have a toasted character. Despite their name, Vienna lagers are generally uncommon in continental Europe today but can be found frequently in North America, where it is often called pre-Prohibition style amber lager (often shortened to "pre-Prohibition lager"), as the style was popular in pre-1919 America. Notable examples include Samuel Adams Boston Lager, Great Lakes Eliot Ness, Devils Backbone Vienna Lager, Abita Amber, Yuengling Traditional Lager, Dos Equis Ámbar and Negra Modelo. In Norway, the style has retained some of its former popularity, and is still brewed by most major breweries.
Lagers would likely have been mainly dark until the 1840s; pale lagers were not common until the later part of the 19th century when technological advances made them easier to produce. Dark lagers typically range in color from amber to dark reddish brown, and may be termed Vienna, amber lager, dunkel, tmavé, or schwarzbier depending on region, color or brewing method.
Tmavé is Czech for "dark", so is the term for a dark beer in the Czech Republic - beers which are so dark as to be black are termed černé pivo, "black beer". Dunkel is German for "dark", so is the term for a dark beer in Germany. With alcohol concentrations of 4.5% to 6% by volume, dunkels are weaker than Doppelbocks, another traditional dark Bavarian beer. Dunkels were the original style of the Bavarian villages and countryside. Schwarzbier, a much darker, almost black beer with a chocolate or licorice-like flavor, similar to stout, is mainly brewed in Saxony and Thuringia.