What is "kellerbier"

Kellerbier is a type of German beer which is typically not clarified or pasteurised. Kellerbier can be either top- or bottom-fermented. The term Kellerbier literally translates as "cellar beer", referring to its cool lagering temperatures, and its recipe likely dates to the Middle Ages. In comparison with most of today's filtered and pasteurised lagers, Kellerbier contains more of its original brewing yeast, as well as vitamins, held in suspension. As a result, it is distinctly cloudy, and is described by German producers as naturtrüb (naturally cloudy). Kellerbier and its related form Zwickelbier are often served directly from the barrel (for example, in a beer garden) or bottled. These beers do not undergo the above-mentioned modern precautions. Thus they are less nonperishable and so it is advisable to drink them as fresh as possible.