Okay a few questions:
-Did you use water in your extraction along with the butter?
-Was the butter salted or unsalted ('sweet cream')?
-Is the residue grainy or does it also appear to have some plant matter in it?
-Do you know the origin of the bud used, or have any info on it?

Have you read the washed cannabutter tutorial sticky in edibles? It's a really good place to start.