Kölsch is a style of beer first brewed in Cologne, Germany. It is unusual because although it is warm fermented with ale yeast, it is then conditioned at cold temperatures like a lager. Which gives it a crisp light flavour style.
In 1986, the brewers of Köln agreed upon the Kölsch Konvention, which set out the brewing process that had to be used and restricted the use of kölsch to breweries that were within 50 km/30 mi of Köln. In 1997, Kölsch became a product with a protected geographical indication (PGI), expanding this protection to the entire EU. Currently thirteen breweries in and around Cologne meet this convention.