Brewed up a batch of Yooper's DFH 60 minute IPA last night. Was shooting for a SG of around 1.065 but ended up at the dreaded 1.046. After I threw a few chairs in the yard and screamed bloody murder
(this is the 5th batch in a row I've hit sub 60's eff), I was cleaning out my mash tun when I noticed about 30% of the grains were intact. I am going to go on a whim here and say this is the cause for my efficiency problems. I always have the guy at my LHBS crush the grains for me so either he doesn't know he has this problem or his crush is set for low efficiency.
I'd hate to question the guy about this because he's been really helpful to me but this is ridiculous.