Lager

Lager is a type of beer which was first brewed in Central Europe some 500 years ago, and has since become the most popular type of beer in the world. The word comes from German and means "storage". Traditionally, the beer is stored for several weeks or longer before being served. Lager is a general term that includes several variations or styles, such as Pilsener, Vienna and Märzen.

Lager is distinguished from ale by its yeast. Lager yeast ferments at colder temperatures and flocculates on the bottom of the fermenting vessel, while ale yeast ferments at warmer 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.

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

The default lager encountered in worldwide production is light in colour and usually represented the helles, pale lager or Pilsener 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, colour, and composition.

In color, while 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.

The flavor of a lager can be quite simple, with the most mild being light lagers. The most complexly-flavored lagers are usually the darkest, although few lagers feature strong hop flavoring compared to an ale 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 commercially produced, Samichlaus, reaching 14% ABV.

Production process

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 for microbrewers 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. 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 favour shallower fermenters in order to control fermentation better; over several generations, evolutionary pressure 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. The composition of a lager can be quite simple or quite complex. 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 colour. 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 corn. 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.

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 as well as the Catholic church. 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 of German ale.

The first lager brewery in the United Kingdom, the Anglo-Bavarian Brewery, was established in Shepton Mallet in Somerset, England in 1864.

Lager dominates the marketplace

In 1953, New Zealander Morton 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 was adopted worldwide, the light lager style emerged, quickly becoming the most popular style of beer in much of the industrialized world.

Since 1950, 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, Japan, France, Italy, Russia and most, if not all, countries where beer is made and consumed.