Mill the grains and mash in with 17 quarts (16 liters) of 151°F (66°C) water to reach about 144°F (60°C). Rest 20 minutes. First decoction: Pull one-fourth to one-third of the thickest part of the mash and bring that to a boil; boil for 10 minutes, then return it to the main mash to bring the total temperature to about 158°F (70°C). Rest 20 minutes. Second decoction: Pull another one-fourth to one-third of the mash for the second decoction and boil it for 10 minutes; return it to the main mash to bring the total temperature to about 170°F (77°C). Rest 10 minutes, then mash out.
Vorlauf until the runnings are clear, then run off into the kettle. Sparge the grains and top up as necessary to obtain about 7 gallons (26 liters) of wort—or more, depending on your evaporation rate. Boil for 120 minutes, following the hops schedule. After the boil, chill the wort to 45°F (18°C) (sic!) and pitch the yeast. When fermentation is complete, lager at 34-37°F (1-3°C) for at least 4 weeks, preferably longer.