In 1307 in the Bohemian city of Plzen (German), the city began brewing beer. Until 1840, most of the beers were top-fermented. In top fermented beers, the yeast that is used settles at the top of the liquid. It has a higher tolerance to alcohol and ferments at warmer temperatures. The taste and standards of quality often varied widely. Because of their dissatisfaction, in 1838, consumers dumped whole barrels of beer into the street to show their dissatisfaction.

Officials of the city subsequently established a city-owned brewery in 1839 called in German: ‘Burger-Brauerei Pilsen’, which today is still produced, known as Pilsner Urquell.

Today, the modern pale lager termed a ‘Pilsner’ may have a very light, clear color from pale to golden yellow, with varying levels of hop aroma and flavor. Typically the alcohol strength is around 4.5% -5% (by volume).

There are varying styles of Pilsner. A few different styles include a German Pilsner that has a pale gold color with a medium hop flavor and a slight note of maltiness. The Czech Pilsner is a straw-colored beer with a noticeable bitter hop flavor that sometimes have a floral aroma. Other European and American Pilsners can range from a bitter or earthy taste to a sweet malt flavor.

More Info: en.m.wikipedia.org