The last time I did it, I did an 11% imperial Stout and added 8oz of Cocoa Nibs and 8oz of Dried Anchos to the Secondary after sanitizing both in Vodka. I let it sit for about a month then bottled, it came out really nice, a good level of peppery heat and flavor, I should have used a bit more chocolate, its there but gets buried by the Peppers.