Contrary to popular belief, lager is not actually a beer style. Lager simply refers to a beer that is bottom fermented. Fermentation starts when yeast is added to the cooled wort (wort is the sweet liquid made from ground malt that has been soaked in water long enough to release it’s sugars), and while there are many different yeasts that are available, there are two principal varieties; top fermenting and bottom fermenting.
Top fermenting yeasts are usually active at warmer temperatures (59-68ºF) and form a foam on the top of the fermenting liquid. The bottom fermenting yeasts used to make lager collect at the bottom the tank and are active at cooler temperatures (around 50ºF). The beer then mellows and becomes smoother as it is stored (lagered: which literally means “put to bed” or “cellared”) at low temperatures for a month or more.
Lagers were invented by the Germans, and Germany is still known to have one of the widest and most popular arrays of lagers today. However, you will likely not find them referring to any of their beers as lagers. Instead the most common varieties are more likely to be referred to as “hell” or “helles” which is related to the English word “yellow”.
Some of the various lager styles include:
- Bock: a strong or potent lager, they usually have an ABV hovering around 6.5% and are often seasonal
- Dortmunder: This is a less popular variety, made by only a few breweries in Dortmund. It has nearly been replaced by the Pilsner. They are usually a golden color and are around 5-5.25% ABV
- Dunkel: A dark lager, the original variety in Germany.
- Schwarzbier: These “black beers” are meant to be the darkest lagers around.
- Pilsner or Pils: The worlds most famous lager style, it literally refers to a product from the city of Plezň. This golden beer is possible only when direct heat replaces warm air in the malting process.