I am at my wits end trying to figure out what I'm doing wrong. I cannot seem to get anywhere close to 70% efficiency with my setup.
according to beersmith, I should have hit 1.082 for an attempted imperial IPA. I had an 18 pound grain bill for a five gallon batch, milled at the LHBS, mashed at 150 degrees for an hour, and fly sparged with 170 degree water over 40 minutes. the mash started out at 151 and had dropped to 148 by the end of the hour, using a ten gallon igloo cooler and a false bottom. the mash itself had the consistency of a soupy oatmeal, but I'm not a hundred percent sure how much water I used. guessing about five gallons. HLT is another ten gallon igloo, sparge is done with a copper coil drilled with holes. I drain the mash, refill with the sparge until it covers the grain bed, and then pull off wort at an even pace to water going in.
after my boil and transfer to primary, there was nothing but sludge left in the pot (remnants of 8 oz pellet hops). it was filtered through a bazooka tube and a sieve. OG showed 1.06, read on two different hydrometers. temperature was close enough to sixty degrees to not warrant a 20% drop in efficiency.
I honestly have no idea what I'm doing wrong. the beers taste fine when they're done, and I've made a few that kick like a mule. I've never had a OG reading that was anywhere close to the target, however. best I can tell, I'm pulling a 50%-55% efficiency with my setup, and that's not acceptable.