Is this a light ale such as a pilsner or a dark brew like a stout? Also, did you brew coffee using hot water, cold water or did you use ground coffee directly? Coffee has a bitterness that is more pronounced when it gets cold. How you introduce it into the wort can affect the bitterness. My plan (when I get around to my first coffee stout) is to brew 16 OZ of coffee in a press using cold water overnight.