Here is a recipe for a kräusened Maibock. The kräusening aids with finishing the beer and conditioning it. This is a light-colored (9 SRM) beer, fairly strong (7.0% ABV), with more hop bitterness (33 IBU) than a traditional bock. The malt, bitterness, and body are well balanced. The key to success in brewing this beer is to pitch an adequate amount of healthy yeast to the main batch and add some vigorously fermenting kräusen beer to the main batch as fermentation winds to a halt. This should take about 4 months to condition (lager) appropriately, but will be well worth the wait.
Edge of Seventeen Maibock
by Chris Colby
All-grain; English units
Edge of Seventeen is a 7% ABV, roughly 17 °Plato bockbier brewed for spring. Lighter in color and more attenuated than a traditional bock, this beer is malty, but balanced by a firm hop bitterness. This recipe employs kräusening to condition the beer. The initial batch of beer is 4.5 gallons, and slightly more bitter than the target; the 2 qt. of kräusen beer added after primary fermentation brings the beer down to its target bitterness, cleans the beer up, and helps the yeast hit the appropriate level of attenuation.
INGREDIENTS (for 5 gallons)
Low in carbonates (less than 50 ppm), low in sulfate (less than 150 ppm); calcium in the 50–75 ppm range
Malt (for an OG of 1.069, at 70% extract efficiency, and 9 SRM)
6.7 lb. Pilsner malt
4.0 lb. Vienna malt
1.5 lb. Munich malt (8–10 °L)
(You will also need 1.25 lb. light dried malt extract for the yeast starter and 0.77 lb. light dried malt extract for the kräusen beer)
Hops (for 33 IBU total)
German Magnum hops (33 IBU)
(0.60 oz. at 16% alpha acids, boiled for 60 minutes)
Tettnang hops (0 IBU)
(0.66 oz., added at end of boil)
Yeast (for an FG of 1.015 and 7.0% ABV)
Wyeast 2206 (Bavarian Lager) or White Labs WLP 820 (Octoberfest/Märzen Lager) yeast
(You will need 2 packages of yeast — one to pitch to the yeast starter and one to pitch to the kräusen beer.)
Yeast starter — Make 2.75 gallons of starter wort with 1.25 lb. of light dried malt extract 6 days before brewday. This will yield wort around SG 1.020. Aerate the wort well and ferment the starter at 55–60 °F. One package of liquid yeast is sufficient to ferment this large starter because of its low original gravity. (Alternately, brew a light, low-gravity lager beer as a starter. For that, you may have to make a “pre-starter,” depending on the beer’s OG.)
Maibock — Mash grains at 151 °F in 17 qts. of brewing liquor. Rest the mash for 60 minutes, then boost temperature (if feasible) to 168 °F and hold for 5 minutes. Recirculate the wort until clear or until 20 minutes elapses. Runoff wort and sparge to collect approximately 7.5 gallons of pre-boil wort. Boil hard with the intention of reaching your post-boil volume of 4.5 gallons in 2 hours. (This is a rate of 1.5 gallons per hour.) Add bittering hops for the final 60 minutes of the boil. Add aroma hops at knockout. Chill the wort to 50 °F, aerate well, and pitch the yeast from the yeast starter. (Make sure the starter yeast is cooled to around 50 °F before pitching.) Ferment the beer at 52 °F. This should take a little over two weeks. After two weeks, and when the fermentation has slowed greatly (and most of the yeast has flocculated), prepare kräusen beer.
Kräusen beer — Make 2.0 qt. of kräusen beer with 12.3 oz. of light dried malt extract. This should make a very light-colored wort at the same specific gravity as your beer. Cool kräusen wort to 52 °F and pitch lager yeast. Ferment beer until high kräusen (the peak of fermentation; most likely the second or third day of fermentation.)
Maibock (cont.) — Transfer the fermenting kräusen beer to a 5.0-gallon carboy and rack the Maibock into it. This should fill the fermenter up to the neck. Affix a blowoff tube and continue fermenting at 52 °F. Replace the blowoff tube with a fermentation lock after a few days (assuming beer is not still being pushed out of the carboy.) The secondary fermentation of the combined main and kräusen beer will not be as vigorous as a normal fermentation and you shouldn’t lose too much beer due to blowoff. When all signs of fermentation cease, wait a few days, then begin lagering the beer. You can do this in a refrigerator — at around 40 °F — or lower the temperature of your fermentation chamber to near freezing. Lager for about 17 weeks, then keg and carbonate the beer to 2.4 volumes of CO2. While the beer is lagering, check the fermentation lock periodically to ensure it doesn’t dry out.