I am drinking my Pliny the Elder after 3 weeks after bottling (after 3 weeks in primary on 2 packs of US-05) and I taste a bitter after taste. It's hard to describe this bitterness (considering it is a BITTER beer), but suffice to say that it is on the unpleasant side. However, the first ever bottle that I tried from this batch, a week ago, did not have this taste, seems like it developed inside the bottle. Also, it is an after taste.
Everything else seems to be fine with the beer. What could this be?