Thirsty Dog Brewing Co.’s Old Leghumper clone

Thirsty Dog Brewing Co.’s Old Leghumper Robust Porter clone

(5 gallons/19 L, partial mash)
OG = 1.068  FG = 1.024
IBU = 24  SRM = 35  ABV = 5.8%

Ingredients
4.5 lbs. (2 kg) extra light dried malt extract
1 lb. (0.45 kg) maltodextrin powder
10 oz. (283 g) crystal malt (20° L)
10 oz. (283 g) crystal malt (80° L)
10 oz. (283 g) crystal malt (120° L)
1 lb. (0.45 kg) chocolate malt
1.5 lbs. (0.68 kg) Munich malt (20° L)
12 oz. (336 g) flaked barley
5.75 AAU German Northern Brewer hops (60 min.)(0.64 oz./18 g of 8% alpha acids)
5 AAU Liberty hops (5 min.) (1.5 oz./43 g at 3.7% alpha acid)
Wyeast 1028 (London Ale) or White Labs WLP023 (Burton Ale) or White Labs WLP013 (London Ale)
1/2 teaspoon isinglass for fining
3/4 cup corn sugar for priming

Step by Step
Steep the grains in 8 quarts (7.6 L) of water at 150 ºF (66 °C) for 30 minutes. Rinse the grains with 1 gallon (3.8 L) of water at 170 °F (77 °C). Add water to make 3 gallons (11 L), stir in the maltodextrin and malt syrup and return to a boil. When the wort begins boiling, add Northern Brewer hops and boil for 60 minutes. Add the Liberty hops for the last 5 minutes of the boil.

Cool wort in an ice bath or with wort chiller. Transfer to primary fermenter and add enough cold water to bring the volume up to 5.25 gallons (20 L). Pitch yeast and oxygenate-aerate well. Ferment this beer on the warm side, at 72 ºF (21 °C) as per the brewer’s instructions, for 7 to 10 days. Add the isinglass to the beer after fermentation is complete to help achieve clarity. Prime, bottle and age for about two weeks.

All-Grain Option: Replace the malt syrup and malto-dextrin with 9 lbs. (4.1 kg) of pale malt and 1.25 lbs. (0.57 kg) of dextrin malt. Mash the grains together.  Fred says Thirsty Dog uses a simple single-infusion mash at 155 ºF (68 °C) for this beer. I would suggest 60 minutes. Change the boiling hops to 6 AAU German Northern Brewer hops (0.75 ounce at 8% alpha acid).  Note that the boiling hops are slightly lower for the all-grain batch, due to greater hop extract efficiency from a full boil of the entire wort. Ferment and condition as described in the extract-with-grains instructions.