Serious Eats: Recipes
Russian Imperial Stout (For Advanced Brewers)
This is an all-grain recipe designed for advanced homebrewers. If your mash tun is not large enough to hold all 21 pounds of grain, you can substitute light dry malt extract for a portion of the 2-row malt. Use a ratio of 0.65 pounds of dry extract for each pound of malt removed. The malt extract should be added after the sparge as the wort is heating to a boil.
I recommend a minimum of 3 weeks in secondary fermentation before bottling or kegging to allow the flavors to meld and the harsher alcohol flavors to subside. If you're not in a hurry, 6 weeks of aging seems to be about perfect time.