103% Efficiency? What Gives

Yeah, having taken multiple hydrometer readings for different parts of the wort and at different times during the transfer to the fermentor, I keep getting the same result. My light lager has now become less so.

17# Pilsen (Dingemans)
1# Biscuit (Dingemans)
.5# Melanoiden
1oz Pearle (90 min.)
1oz Pearle (20 min.)
1oz Hallertauer (10 min.)
1oz Hallertauer (0 min.)

Estimate was 1.047 based on 75% efficiency. My reading(s) were 1.064 at 50 degrees. My PH was at 5.6 and I mashed for 75 minutes at 150.

After day one I took another reading during fermentation and got 1.062 with a different hydrometer.

I weighed, on a different scale, what was left of my new sack of Pils and I have 37# left, so my measurements weren't off.

Any ideas. I've never gotten above 80% on my system....

There's a measurement error somewhere.
1. Weight of grain
2. Volume in fermenter
3. Hydrometer calibration
4. Potential yield of grain

What size sack: 25kg ~ 55lbs yet your total is 37 + 17 = 54?

those ingredients for a 5 gallon batch = 1100
those ingredients for a 10 gallon batch = 1050

Where did the 1047 come from.
And with 18 pounds (which would leave you with 37 pounds left) you get
5G = 1105
10G = 1053

These numbers are assuming 75% Efficiency with pilsner malt at 1036 potentail SG

It's an 11 gallon batch and 1.047 is using Beer Smith. The sack weight was using a bathroom scale and +/- 1lb seemed pretty good since my OG was so far off.

It sounds like you might have measured your wort volume incorrectly. Hard to see without more details.

have you calibrated you hydrometer? It should read 1.000 in water at room temp