March 3, 2014 by Prost Brewing
Before refrigeration, German beer that was to be aged was stored in the rock caverns just outside the village. In the cool caves, the beer could slowly mature in oak over several months, eventually resulting in various unique, one-of-a-kind German lagers different in flavor and their overall sensory profile than their quick and warm-fermenting ale cousins. One such lager, today known in Germany as Kellerbier or literally “cellar beer,” was actually named in reference to the cool “cellar-like” lagering temperatures involved in its production.
Originating in the region of Franconia, Germany, the recipe for Kellerbier dates all the way back to the Middle Ages! Thus, it was the small artisanal breweries of Franconia that spawned a style of beer still drank in abundance in Franconia today.
Some of the Kellerbier’s most noted characteristics arise from the unique set of processes involved in its production. For one, Kellerbier is made with what is called “cask conditioning.” For those of you who are not familiar with the significance of “conditioning” in the beer world, conditioning is simply the process a beer goes through after fermentation to make it ready to dispense. Adding on to this, “cask conditioning” involves a secondary fermentation in a cask. This means that when a cask of Kellerbier arrived to the pub it traditionally still contained active yeast, and upon arrival would be set aside in the pub cellar where it could undergo its “cask conditioning,” hence the name “cellar beer.” Of course, this name could have also been “cave beer” for those breweries who conditioned there Kellerbier in a nearby cave where the beer rested in a cave’s cold interior for months, a method still performed by some artisanal Franconian breweries today.
Once the conditioning was done, these small breweries would traditionally serve the bier directly out of the casks in which they were aged in, a convention that can still be seen to some extent in modern-day Franconia. As would be expected, the bier poured out in a ‘naturally cloudy’ state (or naturtrüb in German), turbid with yeast. Thus, Kellerbier traditionally contains more of its original brewing yeast and vitamins still in suspension.
Another defining characteristic of Kellerbier is its relative lack of carbonation that results in little to no beer head. This is because the bier is often served “ungespunded” as they say in German, which means the bier is “unbunged” or in layman’s terms, “uncorked.” Thus, as Kellerbier matured in a second fermentation within the oak casks, the carbon dioxide produced as a product of the fermentation could escape through the “bung hole” (hole for the cork) instead of being trapped inside like with many other beers.
The final product of such a peculiar set of conditioning techniques is a beer that has survived through the centuries, maintaining and even increasing its popularity with the years passing. We may not yet have a cave (yet!?!) to perform our own cask conditioning for our own Prost Kellerbier, but we do have our own unique play on the traditional German Kellerbier in the form of our “Keller Pils.” Acquiring a gold medal at this past October’s Great American Beer Festival (GABF), Prost Brewing’s Keller Pils is a cellar beer so good you might just want to start storing it in quantity in your own cellar!
Here’s a Prost to Cellar Magic!… “Prost!”