Eisbock

(5 gallons/19 L, all-grain)
OG = 1.067  FG* = 1.014
IBU* = 28  SRM* = 10.6  ABV* = 7%

* The base recipe, and specifications listed above, are for my favorite Maibock recipe before freeze-distillation. Note that once freeze-distilled, these values will change, however to what effect is determined by how much ice you decide to leave behind.

Ingredients
12 lbs. (5.4 kg) German Pilsner malt
0.46 lb. (0.21 kg) melanoidin malt
0.4 lb. (0.18 kg) Carapils® malt 
0.4 lb. (0.18 kg) Weyermann Caramunich® I malt
0.4 lb. (0.18 kg) Weyermann Carahell® (10 °L)
0.4 lb. (0.18 kg) Weyermann Carared® (20 °L)
0.23 lb. (0.10 kg) Weyermann Caraaroma® (150 °L)
3.6 AAU Tettnanger hops (85 min.) (0.9 oz./26 g at 4% alpha acids)
3.8 AAU Hallertauer Mittelfrüh hops (5 min.) (0.9 oz./26 g at 4.25% alpha acids)
1.4 oz. (40 g) Hallertauer Mittelfrüh hops (0 min.) 
Wyeast 2124 (Bohemian Lager) or Wyeast 2206 (Bavarian Lager) or White Labs WLP830 (German Lager) or White Labs WLP833 (German Bock) or SafLager S-23 or Mangrove Jack’s M76 yeast
Lallemand CBC-1 yeast and 2⁄3 cup corn sugar (if priming)

Step by Step
Mash-in at 126 °F (52 °C); rest 15 minutes; raise temperature to 144 °F (62 °C); rest 25 minutes; raise temperature to 162 °F (72 °C); rest 20 minutes; raise temperature for mash-out to 172 °F (78 °C). Lauter as normal.

 Boil 90 minutes, adding hops as indicated. At the end of the boil add the aroma hops and whirlpool for 15 minutes. Cool to 55 °F (13 °C). After the beer reaches terminal gravity (should be approximately 1.014 after 7 to 10 days), reduce temperature by 4 °F (2 °C) per day to about 32 °F (0 °C). Package about four weeks after brew day.

Up to this point you have brewed a Maibock. To turn it into an eisbock, purge your fermentation bucket (ideally one with a spigot at the bottom) with CO₂ to minimize oxygen pickup and then freeze the beer. 

When enough of the beer has frozen to your liking (likely 2–3 days — the longer you freeze it the more concentrated the eisbock will be), drain the higher-concentrated beer into a receiving vessel (such as a Cornelius keg) that has been purged with CO₂. Add CO₂ to the top of the discharging bucket(s), too, as the headspace increases during draining. This also reduces the chance of oxidation. For the same reason, the transfer tube should be long enough to reach the bottom of the receiving vessel. Let the beer settle for a couple of days and then rack it again to help clarify (or filter the beer).

Rack to a keg and force carbonate, or add fresh CBC-1 yeast and priming sugar before bottling.

Eisbock

(5 gallons/19 L, extract only)
OG = 1.067  FG* = 1.014
IBU* = 28  SRM* = 10.6 ABV* = 7%

This extract recipe assumes you can find Weyermann Bavarian Maibock malt extract. If this extract is unavailable in your region of the world, you can steep all the specialty grains in the all-grain recipe and swap out the Pilsner malt with 8 lbs. (3.6 kg) Pilsen liquid malt extract.

Ingredients
8.8 lbs. (4 kg) Weyermann Bavarian Maibock malt extract
3.6 AAU Tettnanger hops (85 min.) (0.9 oz./26 g at 4% alpha acids)
3.8 AAU Hallertauer Mittelfrüh hops (5 min.) (0.9 oz./26 g at 4.25% alpha acids)
1.4 oz. (40 g) Hallertauer Mittelfrüh hops (0 min.) 
Wyeast 2124 (Bohemian Lager) or Wyeast 2206 (Bavarian Lager) or White Labs WLP830 (German Lager) or White Labs WLP833 (German Bock) or SafLager S-23 or Mangrove Jack’s M76 yeast
Lallemand CBC-1 yeast and 2⁄3 cup corn sugar (if priming)

Step by Step
Start heating 5 gallons (19 L) of water. As the water warms, remove from heat and stir in all the extract until fully dissolved. Return to heat and bring to a boil.

 Boil 60 minutes, adding hops as indicated. At the end of the boil add the aroma hops and whirlpool for 15 minutes. Cool to 55 °F (13 °C). After the beer reaches terminal gravity (should be approximately 1.014 after 7 to 10 days), reduce temperature by 4 °F (2 °C) per day to about 32 °F (0 °C). Package about four weeks after brew day.

Up to this point you have brewed a Maibock. To turn it into an eisbock, purge your fermentation bucket (ideally one with a spigot at the bottom) with CO₂ to minimize oxygen pickup and then freeze the beer. When enough of the beer has frozen to your liking (likely 2–3 days — the longer you freeze it the more concentrated the eisbock will be), drain the higher-concentrated beer into a receiving vessel (such as a Cornelius keg) that has been purged with CO₂. Add CO₂ to the top of the discharging bucket(s), too, as the headspace increases during draining. The transfer tube should be long enough to reach the bottom of the receiving vessel to reduce oxidation. Let the beer settle for a couple of days and then rack it again to help clarify (or filter the beer).

Rack to a keg and force carbonate, or add fresh CBC-1 yeast and priming sugar before bottling.