Great Divide Brewery’s Yeti Imperial Stout clone

Great Divide Yeti Imperial Stout clone

(5 gallon/19 L, all-grain)
OG = 1.090  FG = 1.018
IBU = 75  SRM = 60  ABV = 9.5%

Ingredients
15.25 lbs (6.9 kg) American 2-row malt
1.0 lb (0.45 kg) crystal malt (120 °L)
12 oz. (0.34 kg) chocolate malt
12 oz. (0.34 kg) black patent malt
10 oz. (0.28 kg) roasted barley
8.0 oz. (0.23 kg) flaked wheat
8.0 oz. (0.23 kg) flaked rye
14.3 AAU Chinook hops (60 min.) (1.1 oz./31 g of 13% alpha acids)
7.2 AAU Chinook hops (30 min.) (0.55 oz./16 g of 13% alpha acids)
5.3 AAU Centennial hops (15 min.) (0.50 oz./14 g of 10.5% alpha acids)
0.5 oz. (14 g) Centennial hops (5 min.)
Wyeast 1056 (American Ale) or White Labs WLP001 (California Ale) yeast (3 qt./~3 L yeast starter)
0.75 cups corn sugar (for priming)

Step by Step
Mash at 150 °F (66 °C). Boil for 60 minutes, adding hops as indicated above.  Ferment at 70 °F (21 °C).

Partial Mash Option
Reduce the amount of 2-row pale malt to 2.0 lbs. (0.91 kg). Add 9.0 lbs. (4.1 kg) of Mun-tons Light liquid malt extract to the recipe. Heat 2.3 gallons (8.7 L) of water to 161 °F (72 °C). Submerge grain bag(s) and partial mash at 150 °F (66 °C) for 30–45 minutes. (Note: this is just over 6 lbs. (~ 3 kg) of grains, you may need more than one grain bag, depending on size. Putting your brewpot in your oven on its lowest heat setting may help you maintain partial mash temperature.)

Remove grains, rinse grain bag(s) slowly with 1.0 gallon (3.8 L) of water at 170 °F (77 °C). Add water to brewpot to make 4.0 gallons (15 L) of wort; stir in roughly two-thirds of the malt extract. Bring to a boil. Boil for 60 minutes, adding hops at the times indicated in the ingredient list. Add remaining malt extract with 15 minutes left in boil. Cool wort, transfer to fermenter, top up to 5
gallons (19 L), aerate and pitch yeast. Ferment at 70 °F (21 °C).