Kellerbier (literally beer from the cellar) can be divided into two categories: ungespundtes and zwickel. Both are unfiltered, the difference being if a spunding valve was used for carbonation. Spunding valves allow beer to naturally carbonate by allowing only a certain pressure in the tank. If you use a spunding valve, and then serve from the tank, you have a zwickel bier. It is fully carbonated. If you don’t use the spunding valve, you have ungespundtes bier, with carbonation equal to only that which is soluble in the beer at lagering temperatures (ie, considerably lower carbonation than zwickel, much like cask beer has lower carbonation).

You can make either from any kind of lager. Thus, both Snowstorm and the U-bier (pronounced oooo-beer, not you-beer) are in fact ungespundtes, and both served vom Fass (gravity poured from a Bavarian stich-Fass). And both Ryan and Mag were correct, it will be Pilsner.

Here ends your beer lesson for the day…