With most extract producers suggesting that extracts are about 75% fermentable, do we know much as to the composition of the remaining unfermentables? In particular, could what's remaining potentially be a concern when it comes to hop creep when dry hopping extract batches? FWIU, brewers nowadays are trying to minimize how dextrinous their worts are in hopes that it can mitigate refermentation upon introduction of dry hops. I understand that there are other workarounds that one can take, but I was just curious as to whether this is something that extract brewers should take any more consideration of simply based upon the composition of the extract itself. 
