Today was my first partial mash and it was a blast! All went well though I still need to get my process down so I can get better organized. It took an hour and 40 minutes longer than extract.
Anyway, when I was done with the mash, I added some LME and my gravity was 1.034 ( I used a refractometer). Beersmith was expecting 1.033 so all is good! I boiled, hopped, cooled, transferred to a better bottle carboy and took my OG reading from what was left in the pot (.5 gallon). The OG read 1.043 and BeerSmith was estimating 1.038. I took a couple readings and all of them came back the same. What the heck? I've made this recipe many times with all extract and routinely hit 1.036 - 1.039.
I've used this refractometer for 10 -15 batches and have never had a freaky reading. I also routinely take my OG from what is left in the brew pot. Its usually one of the last things I do before I start cleaning.
As for the recipe, I mashed with 2.75 lbs maris otter, and 1 lb of specialty malts. I used 3lb pale LME.
Is taking the gravity reading from the bottom of the pot the problem? Or is something else going on here?
Thanks in advance!