Homebrew recipe provided by Adam McClure, technical support service team member at Imperial Yeast. The recipe was developed from his experience as a professional brewer with suggestions from Imperial Yeast coworkers and other pro brewers in a truly collaborative effort. Hear more advise for brewing and fermentating Collaborator Doppelbock directly from Adam — and get more tips on high-gravity lager fermentation — in this Chop & Brew episode.
Note: Adam suggests brewer perform both Forced Fermentation Test (brew day) and VDK Test (during diacetyl rest) to ensure yeast performance and beer quality. See the links for instructions at Imperial Yeast’s website.
Collaborator Doppelbock
OG: 1.080-1.100SG (20ºP-25ºP)
TG: 1.020 (5ºP)
ABV: ~10.5%
BU: 20
INGREDIENTS
Malt:
- 65% Munich Malt (Low protein continental malt)
- 25% Pilsner (Low protein continental malt)
- 10% Caramunich (60ºL)
Hop:
- German Tettnanger (Or Hallertau Mittelfruh) 10 BU @ 90 min
- German Tettnanger (Or Hallertau Mittelfruh) 10 BU @ 60 min
PROCESS
Mash:
Single Infusion 154ºF @ 1.25qt/lb. Mash at 5.4pH. Rest until starch is converted ~60 minutes. Raise temp to 170ºF.
Boil:
Check pre boil gravity. Should be a minimum of 1.075 (18.75ºP). Boil for at least 90 minutes. Add yeast nutrient 15 min before KO.
KO:
Knockout at 46ºF. Aerate twice as much, or 0.3LPM pure O2 through a stainless sintered stone for 5 minutes.
Yeast:
Pitch rate should be 2.0 million cells/mL/ºP. Choose fresh healthy yeast. L17 Harvest (year round) and L26 Pilgrimage (limited edition strain) are great options. Both strains are balanced, flocculate well and have a higher ABV tolerance.
Fermentation:
Set point 48ºF for the first 48 hours. Adjust to 52ºF for the mid fermentation period. At 2ºP above Terminal Gravity, raise the temperature to 65-68ºF for VDK/diacetyle rest. After several days, run a VDK test. If it passes. Crash to 32ºF for several days.
Conditioning:
Rack to a clean, sanitized and purged secondary vessel. Apply 2 psi head pressure. After 2-3 months, rack to another cleaned, sanitized and purged vessel. Carbonate. Store cold and upright for another 2 weeks before pouring.