lager

Lager is a category of beer that is fermented and conditioned at cooler temperatures using bottom-fermenting yeast. The term derives from the German lagern, meaning to store or lay down, reflecting the long maturation period required to develop a clean, smooth profile. Lagers are typically fermented at around 7–13°C (45–55°F) with Saccharomyces pastorianus and then conditioned for several weeks to months, often at low temperatures to promote clarity and stability. This contrasts with ales, which use top-fermenting yeasts at warmer temperatures to produce fruitier, more varied flavors.

Originating in Central Europe, lager brewing spread from Bavaria and the Czech lands in the 19th century. The development of pale lager culminated with Pilsner, first brewed in 1842 in Plzeň (Pilsen) by Josef Groll using pale malt and Saaz hops. The identification and isolation of the lager yeast by Emil Christian Hansen in the 1880s helped standardize methods. From Central Europe, lager spread worldwide and became the dominant beer style in many markets, influencing brewing worldwide.

Styles of lager range from pale to dark. Pale lagers include Pilsner and Helles, while dark lagers such as Dunkel, Schwarzbier, and Vienna lager offer malt-forward character with varying degrees of roast. Märzen and Bock are traditionally stronger lagers; Czech darker lagers (and other regional variants) provide richer flavors. Color and bitterness are largely determined by malt choice and hopping. Overall lagers tend to be clean, crisp, and highly drinkable with relatively low ester and phenol notes compared with ales.

Brewing involves malted grain, water, hops, and lager yeast, with a mash, lautering, boil, and rapid cooling before inoculation and fermentation at low temperature. After primary fermentation, the beer undergoes lagering, a period of cold conditioning that smooths flavors and reduces unwanted compounds. Lager styles are now produced globally, ranging from mass-market to craft varieties.