Kölsch beer is very much in demand because it must be brewed in Cologne. The Kölsch Konvention of 1986, states very specifically that kölsch cannot be brewed outside of the state. A kölsch is fermented slightly warmer than an altbier, however cooler than the majority of other ales. The brewers use a yeast which produces a lightly fruity taste and aroma, with a hoppy bitterness. Compare and contrast the kölsch and altbier at Beers of Europe.
The kölsch has a long history, stretching back to 874 AD, with production being regulated by the brewing of Cologne since at least 1250 AD. The modern kölsch appeared in the late 1880s as the Cologne brewers wanted to fight back against the influx of imported Bavarian beers. The Kölsch Konvention has made kölsch one of the most strictly defined beers in Germany. According to them, kölsch is a hoppy, bright pale and highly attenuated top-fermenting beer.
It should be served in a tall straight kölsch-“Stangen” glass, according to the brewers of Cologne, as mandated in 1986. It is common in the bars of Cologne to see the Stangen glassware being brought to the table in racks. Each glass only holds 200ml; that keeps the table staff busy!
Whilst the Kölsch Konvention can prohibit the production of Kölsch beyond the boundaries of Cologne, the style has been adopted by others. It is widely brewed by craft breweries in America.