(I replaced 6 lb of 2-row with 2 lb of DME and 2 lb of dextrose from the original recipe so it will fit in the Foundary)

Do a single infusion mash at 150°F (66°C) for 60 minutes. In order to create enough high-gravity wort, you can use a larger mash tun (10 gal/38 l), combine two mashes in the kettle, or supplement with malt extract. After sparging, boil for 60 minutes, following the hops schedule. Add the clarifying tablet and yeast nutrient (to ensure a healthy fermentation) at 15 minutes.

Cool the wort to 66°F (19°C), aerate it or add oxygen prior to pitching, and pitch the rehydrated yeast. (If you’re using liquid yeast, be sure to make an adequate yeast starter.)

Ferment at 66°F (19°C) (see Brewer’s Notes for more details). Be sure to use a blow-off tube!

BREWER’S NOTES
Brewing an imperial stout can be challenging. Here are some tips to help.

Pitch the yeast and let the temperature rise to 68°F (20°C) and hold that over the first 3 days. Raise the fermentation temperature gradually to the low 70s Fahrenheit (20s Celsius) to help the yeast complete fermentation and reabsorb any diacetyl that was produced during fermentation.

Be sure to check your gravity during fermentation to be aware of any potential fermentation issues and to know when you have reached your target gravity.

After 2−3 weeks in the primary, rack the beer off the yeast cake into a secondary fermenter for an extended conditioning period of 2−4 months. Purge the fermenter with CO2 if possible, and keep it in a dark area that has consistent temperatures in the low 60s Fahrenheit (mid teens Celsius).