So for years I've always taken my post-boil OG reading from the fermenter (before pitching) or from the kettle once cooled. Recently I've been having some crazy up and down readings differing between my refractometer and (2) hydrometers and I partially concluded that I wasn't getting a solid "mixed" sampling if you will. Today I chose to take my reading about 55 min into my 60 min boil for two reasons. 1.) It should be mixed extremely well due to the kinetic rolling of the boil 2.) If I'm under my target OG, I can continue to boil a little longer and not risk missing my target. I cooled the small sample quickly. Good news, it was dead nuts for my efficiency. Weird news, I took a few readings once cooled and got some really erratic numbers again. (Yes, everything is calibrated, tested, etc.) I'm assuming it had to do, once again, from "where" I was pulling my samples. Does anyone else use this technique? I'm guessing yes, but didn't think it could hurt to ask. Cheers to a hybrid WC/NE IPA I knocked out today, can't wait to see how she turns out.