Lager

Lager (German: storage) is a type of beer that is brewed using bottom-fermenting yeast at lower temperatures and for longer durations rather than those typically used to brew ales. In German, the term "lager" refers to storing a beer at cool temperatures and does not necessarily imply bottom-fermentation. Pilsner, Bock, Dortmunder Export and Märzen are all styles of lager.

Pale lager is the most widely-consumed and commercially available style of beer in the world. There are also dark lagers, such as Dunkel and Schwarzbier.

History of lager brewing

While cold storage of beer, "lagering", in caves for example, was a common practice throughout the medieval period, lager yeast seems to have emerged as a spontaneous mutation or hybridization somewhere in the Holy Roman Empire.

As a new variety of beer, its production faced opposition from established brewers. Private brewers of lager were often required to produce their beer outside city walls; more traditional brewers produced beer which evolved into the Altbier and Kölsch styles.

While lagers have become the predominant form of beer in America it was not until 1840 that they made their way to America. With the influx of German immigrants during the 19th century it was only a matter of time until the production of bottom-fermenting beers would be produced there. Lagering may have had its roots in Germany but it was John Wagner with his small brewery on St. John Street, near Poplar, Philadelphia who started the first brewery producing lagers in America using yeast strains which he brought with him from Bavaria where he had been a brewmaster.^[1]

In 1953, New Zealander Morton W. Coutts developed a process known as continuous fermentation. Continuous fermentation allowed the production of lager at a much faster pace, albeit with a reduction in flavor development. This development made possible the mass production of lager beer at a rate competitive with ales. As this technology became widespread, the light lager style emerged, quickly becoming the most popular style of beer in much of the industrialized world.

Since 1950, pale lager has displaced ale as the type of beer most consumed in the United Kingdom, and also constitutes the overwhelming majority of beer produced and sold in the United States, China, Australia, India, Japan, France, Italy, Russia and most countries where beer is made and consumed.

Characteristics

As the modern definition of lager relates only to the method of fermentation, the characteristics of lager beers are varied.

The average lager in worldwide production is light in color and usually represents the helles, pale lager or Pilsner styles. The flavor of these lighter lagers is usually mild and the producers often recommend that the beers be served refrigerated. However, the examples of lager beers produced worldwide vary greatly in flavor, color, and composition.

In colour, helles and pale lager represent the lightest lagers at as pale a colour as 6 EBC. The darkest are Baltic porters, which can be as dark as 400 EBC; darker German lagers are often referred to as Dunkel lagers.

Lager yeast ferments at lower temperatures and flocculates on the bottom of the fermenting vessel, while ale yeast ferments at higher temperatures and settles on the tops of fermentation tanks. The organism most often associated with lager brewing is Saccharomyces pastorianus, a close relative of Saccharomyces cerevisiae.

The flavour of a lager can be quite simple, with the most mild being light lagers. Lagers with the most complex flavors are typically the darkest, although few lagers feature strong hop flavoring compared to ales of similar alcohol by volume. In general, however, lagers display less fruitiness and spiciness than ales, simply because the lower fermentation temperatures associated with lager brewing cause the yeast to produce fewer of the esters and phenols associated with those flavours.

In strength, lagers represent some of the world's most alcoholic beers. The very strongest lagers often fall into the German-originated doppelbock style, with the strongest of these, the commercially-produced Samichlaus, reaching 14% ABV.

Production process

A glass of lager

The key difference between an ale and a lager is in fermentation; a lager is fermented at a much lower temperature, and with a different yeast, than an ale. If continuous fermentation is not employed, the primary fermentation period for a lager will take at least twice as long as for an ale; this time is furthermore compounded by weeks or months of lagering. As the low-temperature fermentation, which can take place at temperatures as cool as 0-5 degrees Celsius, allows diacetyl to remain free in the fermenting beer, the fermentation temperature may briefly be raised—a "diacetyl rest" -- near the end of the primary fermentation to allow the consumption of this chemical. This reliance on lower temperatures and better temperature control separated Europe into "lager" and "ale" spheres before the introduction of refrigeration, with warmer countries generally producing ales and colder ones producing lagers. Difficulties in temperature control also create a disincentive problem for microbrewers attempting to produce lagers.

One exception to the rule of low-temperature lager brewing is found in a beer style known as steam beer or California common beer. The strain of yeast used in steam beer was selected by brewers in the German tradition from the central and eastern United States moving west to California during the 1840s and 1850s. The higher ambient temperatures in that region caused brewers to favor shallower fermenters in order to control fermentation better; over several generations, artificial selection led to the emergence of a lager strain which produced the best beer at temperatures of 18-20 degrees Celsius.

The choice of a lager beer's grains and hops is in principle the same as for an ale, despite the nomenclature "lager malt" sometimes encountered in the United Kingdom. Most lagers are brewed in the Continental style, that is, of a style originating in continental Europe, and consequently follow central European recipe formulations: the grain bill is composed mostly of Pilsener malt, Vienna malt or Munich malt with caramel malts added to improve sweetness and head retention and other malts added only for color. The selection of hops is usually from noble hops such as Saaz, Hallertau, Tettnanger, Strisselspalt or Lubelski.

Lagers often also feature large proportions of adjuncts, usually rice or maize. Adjuncts entered American brewing as a means of thinning out the body of American beers, balancing the large quantities of protein introduced by six-row barley. However, 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. However adjuncts are not always used to reduce prices, adjuncts may actually cost more than malt in many cases.^[2]

Pale lager

Pale lager is a very pale to golden-coloured 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 Pilsner Urquell. The resulting pale coloured, 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, and includes the American beer Budweiser, the world's highest volume selling beer.

The main elements of the lagering method used by Sedlmayr and Groll are still used today, and depend on a slow acting yeast that ferments at a low temperature while being stored. Indeed, the German term 'Lager' means 'storage'. While first marketed as 'Lagerbier' in Austria and Germany, the term is now quite uncommon in the German speaking countries where today one would simply ask for 'helles Bier' (pale lager), 'dunkles Bier' (dark lager or ale) or specific varieties, particularly those with a distinctive character such as Pilsner or Weizenbier (also called Weissbier). In the English speaking world, however, lager is now a general name for any beer made using the lagering method.

Dark lager

Lagers would likely have been mainly dark until the 1840s.^[3] Dark lagers may be dunkels, Schwarzbiers, Viennas or Baltic porters. Dunkel is a dark German beer. Dunkel is the German word meaning "dark", and dunkel beers typically range in colour from amber to dark reddish brown. They are characterized by their smooth malty flavour.^[4] 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. Lighter-coloured lagers were not common until the later part of the 19th century when technological advances made them easier to produce.

Schwarzbier, a much darker, almost black beer is mainly brewed in Saxony and Thuringia with a chocolate or near liquorice flavour, similar to stout.

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