The town of Cologne, the namesake for Koelsch, not only has more breweries than any other city in the world, but also has a federal law protecting its right to brew this pale, top-fermenting ale (appellation controlee). Koelsch, which has been brewed in Cologne and outlying areas since before 1300, furthermore has a brewers guild (founded in 1396) that mandates certain parameters for its brewing and protects the appellation worldwide.
Koelsch is typically lighter even than Pilsner in color and is often around 5% ABV with a slightly malty, fairly soft palate. The finish is decidedly dry due to its high attenuation and firm hop character. The cleanness is a result of a fairly long, cold maturation of two to six weeks.