Pilsner

The name refers to the city of Plzeň (Pilsen), where the first beer of the new brewery was released in 1842. In 1889 the Austro-Hungarian consulate general in London reported that a lot of German lager, mainly from Bremen and Hamburg, was being sold there as 'Pilsener Beer'. London customs did not consider that contrary to the law: in London, according to it, 'Pilsener Beer' meant a type of beer, regardless of where it was brewed, at least if the true origin was stated as well. The two breweries in Pilsen rejected that in 1891: in their view, pilsener had to be brewed in Pilsen. That is stated in the brewery's anniversary history from 1892, translated by Peter Dyer in the journal Brewery History.

Today pils is in practice a style name. Dutch law requires for 'pils' a pale-coloured beer with an extract content of the original wort of 11 to 13.5% (not an alcohol percentage) and prohibits fruit and flavourings; the law says nothing about origin. In Germany, according to the Bavarian food authority LGL, the name Pils rests on what is customary in the trade, not on a legal definition.

In the Czech Republic it is different: there, according to the BJCP, only Pilsner Urquell and Gambrinus are called 'Pilsner'. 'Urquell' means 'original source'.

According to Cornell, the story of the smuggling monk appears in far too many sources. Beer historian Martyn Cornell summarised Evan Rail's archive research in 2011. Rail read the 1839 petition with which twelve leading citizens of Pilsen in effect founded the brewery, and the brewery's anniversary history covering 1842–1892.

It shows that the yeast was not smuggled by a monk, and probably was not brought along by brewer Josef Groll either. According to the 1892 book, pitching yeast for the first brew and fermenting wort were bought in Bavaria.

The documents are also clear about the construction. The builder of the brewery visited the largest Bohemian breweries that were already making bottom-fermented beer. The architect travelled to Bavaria in December 1839 to look at large breweries in Munich and elsewhere. To run the new brewery, the 29-year-old Bavarian brewer Josef Groll from Vilshofen was hired.

According to the Historisches Lexikon Bayerns, cold fermentation became widespread in Bavaria from the 16th century, and bottom fermentation was by then already generally known. Pilsen built its Burgher Brewery partly because in 1839 the town was already being 'flooded' by bottom-fermented beer in the Bavarian style.

What was new in Pilsen in 1842 was the colour. With malt kilns on the English model, which were heated indirectly, pale malt was easier to make, whereas Bavarian lagers were still fairly dark at that time. Even that 'first pale lager' is not entirely certain: the BJCP notes that there may already have been earlier pale lagers in Bohemia.

How old lager exactly is, is not settled. What we do know is that before 1883, when Emil Christian Hansen isolated pure culture yeast, yeast cultures, at least in Bavaria, were mixtures of top- and bottom-fermenting yeasts that also contained wild yeasts and lactic acid bacteria. Bottom fermentation in the strictly modern sense therefore did not exist before that.

The 'skunky' or 'lightstruck' smell is a well-known beer defect with a chemical cause. According to research by, among others, Ghent University (Huvaere et al., 2006), it comes mainly from the compound 3-methylbut-2-ene-1-thiol (MBT), which stinks at just a few nanograms per litre. MBT forms because light breaks down the bitter compounds from hops (iso-alpha acids). Riboflavin (vitamin B2) in the beer absorbs the light and starts the reaction; a sulphur fragment, from amino acids among other things, completes the compound. Blue light (350–500 nm) proved the most effective.

That is why the packaging matters. According to the Brewers Association (BA), brown glass protects somewhat, green glass less and clear glass hardly at all. A Molson patent from 1981 confirms with measurements that clear glass lets through the most harmful light and brown glass the least. But even brown bottles do not belong in bright light according to the BA, and according to a guide from CraftBeer.com (also from the Brewers Association) the skunk smell can then form within a few seconds. The BA calls cans 'mini kegs' that protect beer from light.

Heat is bad for beer, but it causes other defects. According to the Brewers Association, lagers stored at 25 °C tended towards caramel-like notes, and at 30–37 °C towards a cardboard taste (ageing through oxidation). A skunk smell is not part of that.