I recently brewed an Imperial Stout with some coffee additions. While I didn't boil the coffee for long (warm steeped 3oz beans and pitched grounds and two cups of brew at flameout), it did lend some unpleasant bitterness to the beer. Unlike hop bitterness, this isn't as pleasing to the tongue. The flavor isn't awful--the beer is still drinkable--but I'm wondering if I should expect it to fade with age. I just completed a 13 day primary, and ended up pretty close to FG. I kegged the beer, and have set it aside to age at 66 degrees (F) for up to a month.
Will the coffee bitterness fade during that time, or should I consign this beer to the "only bring it out after the guests have had a few" shelf?