I did my first partial mash today and man was it a lot more fun! There was a bit of gravity magic happening, which I hope I can attribute to not mixing the top off water well enough. What do yall think?
My 3 gallons of strike water was at 150, mashed for 75 min, then I sorta sparged at 170 with another gallon. The second pot I have wasn't big enough to hold the 8 lbs of grains and a gallon of water, so I poured it through the grain bag as best I could then soaked them in the remaining quarter of a gallon.
Long story short, I used 4 gallons for the mash/sparge, so I assume that I was left with about 3.5 gallons for the boil after the grains soaked up some.
The boil gravity of the 3.5 gallons was 1.054 which comes to about 64% efficiency.
I did my boil as usual, then did a late LME addition of 4.5 lbs. After topping off and shaking, the gravity ready 1.054 again! What?
Doing a bit of math, I found that I should have ended up with an OG of 1.068 given my boil gravity and assuming 34 ppg for the LME.
Is it reasonable to assume that I was taking a reading of top off water? Maybe I missed something in my math?