Maple Imperial Stout

Maple Imperial Stout

(5 gallons/19 L, all-grain)
OG = 1.076*  FG = 1.021
IBUs = ~35  SRM = 45  ABV = 9.6%
* Prior to maple syrup addition

Ingredients
10.5 lbs. (4.8 kg) 2-row pale malt
2 lbs. (0.9 kg) Munich malt 
1 lb. (0.45 kg) flaked oats
1 lb. (0.45 kg) Carafa® III malt
0.5 lb. (0.23 kg) crystal malt (20 °L)
4 oz. (113 g) chocolate wheat malt
8.5 AAU Northern Brewer hops (60 min.) (1 oz./28 g at 8.5% alpha acids)
8.5 AAU Northern Brewer hops (5 min.) (1 oz./28 g at 8.5% alpha acids)
32 fl. oz. (950 mL) very dark maple syrup (secondary)
Wyeast 1318 (London Ale III), White Labs WLP066 (London Fog), or
LalBrew Verdant IPA yeast
3⁄4 cup corn sugar (if priming)

Step by Step
Brewers with access to maple sap may replace all brewing water with sap for this recipe. Those without access to sap can add 0.5 lb. (0.23 kg) corn sugar as substitute. The gravity of maple sap for this recipe is assumed to be ~1.005, though this will vary — take a gravity reading of the sap before brewing to adjust accordingly. 

Mash grains in sap at 154 °F (68 °C) for 60 minutes. Sparge as normal and boil for 60 minutes adding hops according to ingredients list. Cool the wort to fermentation temperature and aerate the wort if using a liquid strain.

Ferment at 69–72 °F (21–22 °C).When primary fermentation is complete, rack beer to secondary vessel, then add 32 fl. oz. (950 mL or 2.8 lbs./1.3 kg) very dark (previously called Grade C) maple syrup. Allow two to three weeks for additional fermentation before packaging as normal.

Maple Imperial Stout

(5 gallons/19 L, extract with grains)
OG = 1.076*  FG = 1.021
IBUs = ~35  SRM = 45  ABV = 9.6%
* Prior to maple syrup addition

Ingredients
6 lbs. (2.7 kg) extra light dried malt extract
1 lb. (0.45 kg) Munich dried malt extract 
0.5 lb. (0.23 kg) Carapils® malt
1 lb. (0.45 kg) Carafa® III malt
0.5 lb. (0.23 kg) crystal malt (20 °L)
4 oz. (113 g) chocolate wheat malt
8.5 AAU Northern Brewer hops (60 min.) (1 oz./28 g at 8.5% alpha acids)
8.5 AAU Northern Brewer hops (5 min.) (1 oz./28 g at 8.5% alpha acids)
32 fl. oz. (950 mL) very dark maple syrup (secondary)
Wyeast 1318 (London Ale III), White Labs WLP066 (London Fog), or
LalBrew Verdant IPA yeast
3⁄4 cup corn sugar (if priming)

Step by Step
If available, replace all brewing water with sap. If not, add 0.5 lb. (0.23 kg) corn sugar as a substitute. 

Place all the crushed grains in a large muslin bag. Begin heating 4 gallons (15 L) of water and submerge the grains in the water. When the water reaches 170 °F (77 °C) remove the grain bag and allow it to drip back into the kettle. Turn off heat and add the malt extract. Stir until all the extract is dissolved then bring wort to a boil. Add the first hop addition at the start of the boil and second addition with five minutes left in the boil. Cool the wort to fermentation temperature, top up to 5 gallons (19 L) and aerate the wort if using a liquid strain. 

Ferment at 69–72 °F (21–22 °C).When primary fermentation is complete, rack beer to secondary vessel, then add 32 fl. oz. (950 mL or 2.8 lbs./1.3 kg) very dark (previously called Grade C) maple syrup. Allow two to three weeks for additional fermentation before packaging as normal.