Originally Posted by Nostrildamus
Start simple and work towards the more complicated. The poster with the suggestion regarding malt type and it having a grainy taste offers a very good starting point as well.
I often agree with that statement, and I am glad you brought up a possible explanation that none of us thought of. However, there is something to be said for starting with the most common cause of a problem, rather than just the most simple, and going from there.