Traditional German Bock

Traditional German Bock

(5 gallons/19 L, all-grain)
OG = 1.072  FG = 1.013
IBU = 25  SRM = 13  ABV = 7.7%

This recipe calls for a triple decoction mash and a 90 minute boil. Be prepared for a long brewday, but the reward at the end will be well worth the extra efforts.

Ingredients
8 lbs. (3.6 kg) German Pilsner malt
2 lbs. (0.91 kg) Pilsner malt, toasted (see step-by-step)
5 lbs. (2.3 kg) German Munich dark malt (9 °L)
1 oz. Hallertau Tradition hops (60 min.) (1 oz./28 g at 5.8% alpha acids)
2.9 AAU Hallertau Tradition hops (20 min.) (0.25 oz./7 g at 5.8% alpha acids)
1.9 AAU Tettnanger hops (20 min.) (0.25 oz./7 g at 3.8% alpha acids)
Wyeast 2206 (Bavarian Lager) or White Labs WLP820 (Oktoberfest/Märzen Lager) or Mangrove Jack’s M76 (Bavarian Lager) yeast
3/4 cup corn sugar (if priming)

Step By Step
About one week prior to brewday toast the 2 lbs. (0.91 kg) of Pilsner malt in the oven at in 350 °F (177 °C) oven for 15 minutes. Two days prior to brewday, make an appropriate sized starter if using the liquid yeast strain. Use 2 sachets if using dried yeast.

Add approximately 22.5 qts. (21.3 L) of water at 99 °F (37 °C) to hit the first strike temperature of 95 °F (35 °C). Hold for 15 minutes. At the end of this time, draw off about 40 percent of the mash into a separate pot, leaving as much liquid behind as possible. Maintain the temperature of this rest mash during the decoction.

First Decoction: Raise the temperature slowly, about 5 °F (3 °C) per minute, to 155 °F (68 °C). Hold for ten minutes, then raise the temperature quickly to boiling. Boil for 30 minutes, stirring occasionally to avoid scorching. Then transfer the boiled mash to the rest mash two cups at a time, until the rest mash is at the next strike temperature, 122 °F (50 °C). Set any remaining decocted mash aside until it cools to 122 °F (50 °C), then stir it into the mash. Let the mash rest for 15 minutes, then proceed to the second decoction.

Second Decoction: Again draw off about 40 percent of the mash, leaving behind as much liquid as possible. Raise the temperature 5 °F (3 °C) per minute, to 155 °F (68 °C), hold for ten minutes, then raise the temperature quickly to boiling. Boil for 30 minutes. Transfer the boiled mash to the rest mash two cups at a time until the rest mash is at the next strike temperature, 155 °F (68 °C). Set any remaining decocted mash aside until it cools to 155 °F (68 °C), then stir it into the mash. Let rest for 15 minutes, then proceed to the third decoction.

Third Decoction: In this decoction instead of boiling the thick part of the mash, we’ll be boiling the liquid part of the mash. Draw off 40-50 percent of the liquid and bring it quickly to a boil. Hold for at least 30 minutes.

Test the rest mash for conversion with iodine as described above, then add the decocted liquid back to the rest mash until the mash-out temperature of 170 °F (77 °C) is reached. Set any remaining liquid aside until it cools to 170 °F (77 °C), then stir it back into the mash. There are two reasons we’re boiling the liquid at this point:

1. That’s where the sugars reside now, so boiling the high-gravity liquid will contribute greatly to maltiness and color by caramelizing some of the sugars in the liquid.
2. Since we’re no longer concerned with preserving the amylase enzymes now that conversion is complete, it’s to our advantage to disable them. That way the dextrins in the mash, which contribute to body and head retention, aren’t further converted into fermentable sugars, resulting in a thin beer.

Let the mash rest at the mash-out temperature for 10 minutes, then transfer to the lauter tun if a combination mash/lauter tun isn’t being used. In either case thoroughly stir the mash so the heavier husks settle out and form a well-stratified filter bed.

Proceed with the sparge, stopping when you’ve collected 7 gallons (26.5 L) of wort. Boil the wort for a total of 90 minutes, adding hops per the schedule indicated. Reserve two quarts of wort for later use in priming the beer.

Chill the remaining wort to about 60 °F (16 °C) and pitch the yeast. Transfer the fermenter to a 50 °F (10 °C) refrigerator for three to four hours after pitching and ferment for seven to 10 days, then transfer to a secondary fermenter.

When the beer is clear (three to five weeks), rack to the bottling bucket into which the reserved priming wort has been poured. Bottle as usual.