Batch size: 5 gallons (19 liters)
Brewhouse efficiency: 73%
OG: 1.078 (post-boil, pre-freezing)
ABV: 8.2% (pre-freezing; final ABV will depend on level of concentration)
10 lb (4.5 kg) Munich malt (9L)
5 lb (2.3 kg) Pilsner malt
6 oz (170 g) Carafa I
6 oz (170 g) British Crystal 65L
6 oz (170 g) Briess Extra Special Roast
4 oz (113 g) Chocolate rye
1 oz (28 g) Styrian Goldings [5% AA] at 60 min.
1 oz (28 g) Styrian Goldings [5% AA] at 10 min.
White Labs WLP830 (German Lager)
Mill the grains and mix with 5.1 gallons (19.4 l) of 159°F (71°C) strike water to reach a mash temperature of 148°F (64°C). Hold this temperature for 90 minutes. Vorlauf until your runnings are clear, then run off into the kettle. Sparge the grains with 2.1 gallons (8 l) and top up as needed to obtain 6 gallons (23 l) of wort. Boil for 60 minutes, following the hops schedule.
After the boil, chill the wort to slightly below fermentation temperature, about 48°F (9°C). Aerate the wort with pure oxygen or filtered air and pitch the yeast.
Ferment at 49°F (9°C) to start and slowly ramp up by about 1°F (0.5°C) per day until you reach 60°F (16°C). Hold until fermentation is complete. Upon reaching terminal gravity, transfer to a keg and drop the temperature to subfreezing, and monitor for ice formation. Depending on your temperature, this could take anywhere from 4 to 12 hours. When you estimate that the mixture is about 20 percent slush/ice and 80 percent beer, rack out from under the slush layer.
Determine total concentration by comparing your new volume to your starting volume (your goal is about 25 percent concentration), and adjust the estimated ABV accordingly. Bottle or keg the beer, and carbonate to approximately 2.25 volumes of CO2.