For the thinking behind this recipe, see Make Your Best British Strong Ale. Also see below for an extract version.
Batch size: 5 gallons (19 liters)
Brewhouse efficiency: 72%
10 lb (4.5 kg) Maris Otter
1 lb (454 g) British amber
8 oz (227 g) British crystal 45L
8 oz (227 g) British crystal 90L
8 oz (227 g) Special B
8 oz (227 g) aromatic
2.75 oz (78 g) East Kent Goldings at 60 minutes [41 IBUs]
1 oz (28 g) East Kent Goldings at flameout/whirlpool [5 IBUs]
Wyeast 1318 London Ale III
Mill the grains and mash at 152°F (67°C) for 60 minutes. Vorlauf until the runnings are clear, then run off into the kettle. Sparge and top up as necessary to get about 6 gallons (23 liters) of wort—or more, depending on your evaporation rate. Boil for 60 minutes, adding hops according to the schedule. At flameout, conduct a whirlpool step: Stir 5 minutes to create a vortex, then add whirlpool hops and allow 20 minutes to settle. After the whirlpool, chill to about 60°F (16°C), aerate well, and pitch the yeast. After 5 days, allow the temperature to rise to 65°F (18°C) for 3 days, then allow it to rise up to 70°F (21°C) until fermentation is complete. Crash, package, and carbonate to just less than 2 volumes of CO2.
Replace the base malt with 10 lb (4.5 kg) of Munton’s Maris Otter liquid malt extract (LME). Steep the specialty grains at 160°F (71°C) for 30 minutes, then remove the bag and allow it to drain into the wort. Add the LME and stir until completely dissolved. Top up as necessary to get about 6 gallons (23 liters) of wort, bring to a boil, and continue as above.