What is lager?
The average beer drinker will think of lager as a refreshing, smooth and easy to drink light coloured beer of around 5% alcohol. This is not surprising, because this form of lager is by far the most widely consumed beer style in the world. Depending on where you are, it can also be referred to as Pils, Helles, Märzen or simply lager.
In fact, lager is a collective name for many bottom-fermenting beer styles, where the colour varies from dark brown to light blonde and the alcohol percentage ranges from alcohol-free to over 10%.
Difference between ale and lager?
Ale is top-fermenting beer, lager bottom-fermented. This is the most common way of distinguishing between beer types, especially since yeast is the most important component of beer. The brewmaster of Lagunitas says "yeast makes beer, brewers make wort". Yeast is the soul of beer and it provides the majority of the flavour components.
With this knowledge, it is logical to divide beer into either top-fermenting or bottom-fermenting. An important difference is the fermentation temperature, which is roughly 8-12 degrees for lager and 17-25 degrees for ale. Bottom-fermenting yeast usually gives off fewer flavours, so that the flavours of the malt and the hops come to the forefront. Top-fermenting yeast releases more flavours, recognisable as fruity and / or spicy flavours.
How is lager made?
As with any beer, a brewer first makes wort, a sugar-rich liquid made from malt and hops. The composition of the wort naturally has a major influence on the final product. If a lot of dark malt has been used, the beer will become dark, the more sugar in the wort, the more alcohol it eventually contains (potentially), and so on. The difference is therefore mainly made during fermentation, with bottom fermentation in the case of lager.
The yeast used for lager is called Saccharomyces carlsbergensis, named after the brewer, Christian Hansen. It is he who is responsible for cultivating this pure yeast strain at the end of the 19th century. It is also called Saccharomyces pastorianus, after Louis Pasteur. Same yeast, different name. It is a slow-growing yeast that functions best under cool conditions (8-12 degrees Celsius).
The word lager comes from the German word lagern, which means "to store". Bottom fermentation beers need a longer rest period after the main fermentation that occurs in cold conditions (around 0 degrees) compared to top fermenting beers. This rest period (or storage) is called lagering and that is why we call all these beers lager.
Saccharomyces carlsbergensis is probably a cross between Saccharomyces cerevisiae (top-fermenting brewer's yeast, for Ale) and an until 2011, an unknown yeast strain. It wasn’t until 2011 when scientists discovered Saccharomyces bayanus wild, in the Patagonian nature that this was known. It is now understood that this is the yeast strain that forms the other part of the cross. It is widely assumed that this Patagonian Bayanus strain reached the higher regions of central Europe (present-day Austria, southern Germany and the Czech Republic) around the 16th century and crossed with Cerevisiae. This cross breed thrives well in these areas, the cold months produced some truly excellent beers.
Although there was still no knowledge of how yeast works, brewers understood that yeast could be "harvested" at the end of fermentation and then reused, with a stable end result. As mentioned before however, this yeast was not isolated until the 19th century.
Difference between lager and pilsner?
Pilsner is a type of lager, named after the Czech city Plzen. It was first brewed in 1842 by the Bavarian brewer Josef Groll. Groll was asked by the people of Plzen to come and brew a good and stable beer, as the quality of the beer at that time was rather disappointing. He brought yeast from Bavaria with him, the yeast used to brew lagers. With this yeast, the very soft water of Plzen, the refined hops that were available and a long lagering time, Groll made a clear beer, golden in colour and crisp in character. It was much appreciated, so much so that the beer still exists today: Pilsener Urquell. A must try and good place to start if you want to explore Pilsner. Pilsener Urquell has a patent on the name Pilsner in the Czech Republic. All the other lager is therefore called Světlý Ležák, which translates as Blond lager.
A good Pilsner is a fairly dry, spicy and hoppy lager.
Difference between beer and lager?
All lager is beer, but not all beer is a lager. Both are a collective name for bottom-fermenting beer types. Pilsner, helles lager, Dortmunder, Bock and Märzen are examples of beers that are part of the lager family.
Dark lager and pale lager
The light-coloured lagers are the best known, dark ones are of course also available. Weihenstephaner Korbinian, a beautiful example of a classic, bottom- fermented German Bock. Dunkel (dark in German) is a fairly sweet, malty beer from Bavaria. Schwarzbier (Black beer in German) is the darkest and driest variant, with roasted notes. It is similar to the dark version from the Czech Republic: bohemian dark lager, Černé in Czech, which is usually slightly sweeter than Schwarzbier.
Apart from pilsner, the Bavarian helles lager is the best-known light-coloured lager. Helles means pale in German. It is an easily drinkable beer, slightly more malty than hoppy and above all, clean and crisp. It was first brewed in 1894 by Späten from Munich and was the Bavarian answer to the successful Pilsner.
Märzen is originally the lager that was drunk during the Oktoberfest. It is a heavier, amber-coloured beer with a hint of caramel. Pretty drinkable, but not quite drinkable enough for Oktoberfest. Instead, they developed a special Fest beer, a heavier helles lager that is dangerously easy to drink. In Austria, however, Märzen is a blond beer, which seems very much (almost the same) as helles lager. Vienna lager is an amber-coloured variant that has many similarities with the helles Lager. It is slightly sweeter and heavier than helles, with a hint of caramelised malt. It sits between traditional German Märzen and helles. Brooklyn Lager is a good example, in the American way: with an extra push of the hops.