Trying to calculate my mash efficiency from my first all-grain batch. Using a recipe I found on-line for an Anchor Steam clone:
9.0 lbs German pils malt
1.0 lbs 40L Crystal Malt
0.5 lbs Special Roast
Mashed at 148F, batch sparged at 160F.
Calculated the expected gravity units to be 372 for 100% efficiency (used tables from Designing Great Beers by Ray Daniels), using extract potential of 1.036, 1.034, and 1.027 for each grain respectively.
I collected 6.5 gallons of wort from the mash tun after final sparge (batch sparged), and gravity at 60F was 1.042. Boiled, and was able to get around 5.25 gallons into fermentor, with SG of 1.049 at 60F.
Calculated either 73.5% or 69% efficiency. Am I correct?