i had a porter on tap (something like the edmund fitzgerald clone in the recipe section) that started developing some soapy off-flavors. i think i left it in contact with the yeast a bit too long. early last week i cold-steeped 1/8 of a pound of allegro (whole foods brand) mocha java in a pint of water and added it to the keg. it tastes phenomenal. i know it's a bit of a cop out but at least i saved 4 gallons or so of beer.