Until the mid-1840s, most Bohemian beers were top-fermented, dark and cloudy. The taste and standards of quality often varied widely, and in 1838, consumers dumped whole barrels to show their dissatisfaction. The officials of Pilsen founded a city owned brewery in 1839, called Bürger Brauerei (Citizens' Brewery - now Plzeňský Prazdroj), brewing beer according to the Bavarian style of brewing. Bavarian brewers had begun experiments with the storage (German: 'Lager') of beer in cool caves using bottom-fermenting yeasts, which improved the beer's clarity, flavour, and shelf-life. Most of this research benefited from the knowledge already expounded on in a book (printed in German since 1794, in Czech since 1801), written by František Ondřej Poupě (1753–1805) from Brno.
The Bürger Brauerei recruited the Bavarian brewer Josef Groll (1813 – 1887) who, using new techniques and the newly available paler malts, presented his first batch of modern pilsener on 5 October 1842. The combination of pale colour from the new malts, Pilsen's remarkably soft water, Saaz noble hops from nearby Žatec (Saaz in German) and Bavarian-style lagering produced a clear, golden beer which was regarded as a sensation.
Improving transport and communications also meant that this new beer was soon available throughout Central Europe, and the Pilsner Brauart style of brewing was soon widely imitated. In 1859, “Pilsner Bier” was registered as a brand name at the Chamber of Commerce and Trade in Pilsen. In 1898, the Pilsner Urquell trade mark was created to put emphasis on being the original brewery.
The introduction to Germany of modern refrigeration by Carl von Linde in the late 19th century removed the need for caves in which to store the beer and thus allowed the brewing of bottom-fermenting beer in many places which had been unable to do so before. However, even until recently the Pilsner Urquell brewery still fermented its beer using open barrels in the cellars underneath their brewery. This technology was changed in 1993 with the use of large cylindrical tanks; however, small samples are still brewed in a traditional way for taste comparisons. Pilsner also has the unique claim to being "the world's first golden beer".
A modern pilsener has a very light, clear colour from pale to golden yellow, and a distinct hop aroma and flavour. Czech pilseners tend toward a lighter flavour (good examples being Pilsner Urquell and Staropramen), while those in a German style can be more bitter (particularly in the north, e.g. Jever) or even "earthy" in flavour. Distinctive examples of German pilseners are Aktienbrauerei Kaufbeuren Jubiläums Pils, Augustiner Pils, Beck's, Bitburger, Flensburger Pilsener Fürstenberg, Henninger's Kaiser Pilsner, Holsten, König Pilsner, Königsbacher Pilsener, Krombacher, Külmbacher, Radeberger, Schwelm's Schwelmer Pils, Veltins, Warsteiner, Würzburger Hofbrau, and Wernesgrüner. On the other hand, Dutch (Amstel, Grolsch, Heineken) and Belgian pilseners (Jupiler, Stella Artois) have a slight sweet taste. Pilseners are identified by their participation in categories like "European-Style Pilsener" at the World Beer Cup or other similar competitions.