maiboch to iceboch

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).

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).