Thanks for all the thoughtful replies.
Upon inspection in a decent light before bottling I found a serious case of stratification going on. My initial tasting samples had been from the very bitter and astringent top layer, when I sampled a nice mixture of the two layers the beer tasted fine...
So, first of all, my brother and I have been homebrewing for a year or so, mostly extracts and starting to branch out into partial mashing. I've had pretty good luck with tweaking recipes and have always ended up with very good results.
I've got a problem with my latest batch, however. I was...