It all started out innocently enough. Brew a tasty fall treat -- a wonderful not-quite winter warmer -- a Doppelbock. This high gravity lager should be around 8% alcohol, said I. Then I got an idea. So, come a warm March weekend, I embarked upon a six-month adventure to ultimately create an Eisbock beer.
Eisbock is German for “ice bock”. Kulmbacher claims to be the originator of the style, dating back to a cask of bock accidentally left out in the winter cold. As ethanol has a lower freezing point than water, freezing and then removing the water concentrated the beer to a rich, potent brew.
My Doppelbock finished primary fermentation after four weeks at 50 degrees. I racked to secondary, dropped the temperature over five days to 34 degrees and lagered for four months. I then racked to a corny keg and dropped the temperature to 28 degrees. After about 24 hours the beer started to get slushy. At this point, I racked the liquid that was not frozen into a new corny keg.
The ice that was left behind was about one gallon of liquid. Distilling, er... I mean condensing the beer, from five gallons to four gallons, left a very malty and slightly sweet brew with an abv of approximately 12%.
The color of this beer should a deep copper color with ruby highlights. Due to extensive lagering the clarity should be excellent. Some caramel notes are evident with minimal hop presence -- just enough to keep it from crossing over to cloying. The finish should be mostly malt and alcohol.
It is a very popular beer around here and is not going to last very long. With a replenishment lead-time of five months it is definitely time to start a new batch!