I always had low efficiency in the past and now that I'm getting back into brewing I'd like to address this. Today's mash was 10 lbs of Rahr 2-row and 10 lbs of Rahr wheat. 5 gallons pre-boil clocked in at 1.073, which according to the web calculators is something like 48% efficiency. Yikes!
I batch sparge with one of those blue igloo ice cubes with SS braid. My first infusion was 6.25 gallons - 1.25 qt/lb. I mashed for 90 mins and the iodine test was clear. First wort was 3 gallons at 1.079. The second batch was 2 gallons for a total of 5 gallons in the kettle.
My pH seems a bit high. My strike water was 6.49. After 15 mins, the mash pH was 5.90 @ 32.8 dC, which I think means I was still about 0.4 points high at mash temp.
I don't expect to be able to get 80% with beers this big, but surely I should be able to get closer to 60%, no? What about a pro brewery, how do they get good efficiency with big beers?