We've made 4 different Coffee porters and added coffee in several diff ways, but my favorite so far, that seems to have imparted the most flavor, is to just grind up the beans and throw in at end of boil. The brewmaster hated this because some grounds stuck around in secondary, and clogged his keg hoses, but I bottle so Im unconcerned about such things.
The other method we did was grind up beans, soak in vodka for days, then strain thru coffee filter into primary. Never tried actually brewing it separately and adding liquid to batch. Anyone who has tried both ways, how would the flavor it imparts differ than what we did?