My last just had horrible efficiency and I am struggling on why? I usually average around 68. Lowest probably was 65 highest was 72%
I had around 45% on my last brew.
SRM 5 in color
Batch sparge
grain bill was
Belgain pils 10lbs
and 2lb wheat
Crush was pretty good I think it could have been better from a LHBS but do not think it was bad enough to give an efficiency in the 40's. Same crush as all previous beers for over a year.
I did notice after batch sparging, the way the grain bed looked it may have gotten some channeling, grain bed was in kind of a dome shape...That is the only thing I can think of any input?

Do you often brew with wheat? Difference in kernel size etc can sometimes give a different crush vs. barley. Depending on your system, even if the wheat doesn't cause a stuck sparge, it may be contributing to channeling, but that is typically more of a problem for fly spargers. Was your volume balanced between mash and sparge?

Pretty pale grist. What water were you using? Mash Temp? If it was 147 ish it takes much longer than 154 especially with a high mash pH.

my understanding with batch sparging is that channeling doesn't matter because your draining the MT then adding a shit load of water and then stiring the shit out of it your (forcing the rinse by stiring and not slowly trickling water through the grain bed), sit for 10 minutes then recirc and drain again. this is what i do with batch sparging and my efficiency is always between 69-72% with grain milled from MoreBeer and LHBS

Yeah, channeling is more of a problem in fly.

I would say ur refrac or hydrometer was off or ur math may have been wrong. Could also be the crop of grain

pretty close, I planned on mashing 1.5 or 1.75 qt per lb but forgot to change it and mashed in at 1.25 qt per lb.
I have brewed with wheat before in small amount like this

Yeah, 2 lbs isn't much... had a friend that had similar issues recently, but his batch was close to 50% wheat and he'd never used it before, so we figured that was likely the culprit..