I had bought some grain from an outfit in Minnesota a few times and my efficiency went way down on all of my beers. Thought I wasn't hitting my temps, and/or lautering too fast, etc. Finally figured out the crush was the issue and quit ordering from them.

I called in an order and spoke with Todd and told him I wanted to make sure the crush was good, so he said he'd double crush them for me and then I could see what I thought. Good lord! It was like flour! Awesome efficiency, but it took an hour to collect first runnings and another hour to lauter the rest off. I never ordered a double crush from him again