Lager

Lager is a well attenuated beer brewed in cool conditions using a slow-acting brewers yeast, known as a bottom-fermenting yeast, and then stored (or "lagered") for a period in cool conditions to clear away particles and certain flavour compounds to produce a clean taste. The most popular examples of beer brewed using the lager method are pale lagers, also known as largers.

History

In the nineteenth century Bavarian brewers used to store their beer in cool places to mature it. They called the beer they obtained "Lagerbier", from the German lagern ("to store"). Over the centuries Bavarian brewers developed a special kind of yeast in order to mature their cold-matured beer. The most apparent difference between ales and lagers is that lagers use bottom-fermenting yeast. As the name implies the yeast settles to the base of the fermentation vessel. However, the most common modern fermentation system is the cylindro-conical tank where the distinction between the different flotation characteristics of the yeasts becomes less clear.

In the period 1820-1830, a brewer named Gabriel Sedlmayr II the Younger, whose family was running the Spaten Brewery in Bavaria went around Europe to improve his brewing skills. When he returned, he used what he had learned to get a more stable and consistent lager beer. The Bavarian lager was still different from the widely-known modern lager; due to the hardness of Munich water it was quite dark.

The new recipe of the improved lager beer spread quickly over Europe. In particular Sedlmayr's friend Anton Dreher used the new lagering technique to improve the Viennese beer in 1840–1841. The Viennese water enabled the use of lighter malts, giving the beer an amber-red rich colour.

The new recipe reached Bohemia, too, and the technique was further improved. In 1842, in the town of Plzeň, a 29-year-old Bavarian brewer Josef Groll tried the new lagering recipe using a different malt with the local water, which was much softer than Munich or even Viennese water: the resultant beer had a very bright golden color. This new kind of beer, which became known as Pilsener or Pilsner, had a huge success and spread all over Europe.

Pilsner

Pilsner is light in color and relatively high in carbonation, with a noble hop flavour and an alcohol content of around 4-5% by volume. Pilsner Urquell ("Original Pilsener") is the prototypical example of pilsner beer.

Most of today's pale lagers are based on Pilsner style beers.

Etymology

The word "lager" stems from the German lagern ("to store"), and refers to the practice of storing beer at a cold temperature to allow the beer to self-filter.

Lagered beers run the gamut from sweet to bitter, and from pale to black. Most lagers are of pale to medium color, with high carbonation, medium to high hop flavor, and alcohol content of 3–5 percent by volume.

Brewing technique

"Lager" yeast, known as Saccharomyces pastorianus or Saccharomyces carlsbergensis, ferments at cool temperatures, and flocculates (forms a cloudy mass) on the bottom of the vat.

"Lager" yeast is a bottom-fermenting yeast, and typically undergoes primary fermentation at 7-12°C (45-55°F) (the "fermentation phase"), and then is given a long secondary fermentation at 0-4°C (30-40°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 "crisper" or "cleaner" tasting beer.

After fermentation, bottom fermented beers are then stored in refrigerated cellars for lagering (maturing and clarification). Quality "Lagers" are stored at a low temperature (as low as 0°C/32°F) for several weeks to several months, clearing, acquiring mellowness, and becoming charged with carbon dioxide. With modern improved fermentation control and less discerning customers, commercial lagers (especially for the British market) only receive short periods of cold storage, typically 1–3 weeks.