Thanks gents.
Now to figure out why my pre-boil gravity was 25 points below what Beersmith suggested it should have been.
-I used 42 qts of water for 32lbs of grains, or a 1.3:1 ratio.
-Heated up my mash tun with 175 degree water, let it settle to my strike temp of 168, added my grains and it settled to 155.5, and only dropped to 150 by the end of the hour
-My water was bottled water, to which I added some PH5.2 conditioner
-Double-milled my grains at LHBS to improve my crush
-I stirred vigorously when adding the grains, and every 15 minutes along the way. No dough balls.
-At the end of 60 minutes, I stirred one last time, vourlauf'd, and then drained in to my kettle, only yielding 5.5 gallons instead of the 6.5 I expected.
-Sparged with ~180 degree water, using 6.5 gals to make up for my missing volume. Stirred in the hot water, let it set a minute and then drained.
I ended up with 12gals of 1.042 wort. BS suggested 1.067 using 73% mash efficiency. Measured eff = 46%
So I'm trying to figure out what happened. Temps seemed right on.
I had hoped the double-crush would do it... I'd estimate the mill roller gap as having been 2 credit-card thicknesses.
The fact that I got 1gal less volume out of the initial mash is odd. I don't
think that was a stuck manifold, as when I sparged, that extra water didn't "show up". Would 32 lbs of grains really absorb 25% more water than the calculators suggest?
Even if it did, as long as I sparged with the right amount to hit the correct volume, absorption shouldn't throw off my sugar extraction like that, right?
Is 60 mins too short for a mash of that amount of grain?
I've read that lack of calcium in the water can stifle conversion... I don't have a water profile. My buddy had pH test strips that only had a "color key" up to 4.4, but the strip color was off the end of the scale so it was above 4.4, but not sure how close to exactly 5.2...
Any other thoughts/suggestions? To have been THAT low was a bit of a bummer.
I compensated by running another gallon of left over hot sparge water thru to get every last bit of sugar I could out, and then boiling vigorously as I could, for longer than normal before starting my hop schedule. I also tossed in a bit of DME I had. The result was slightly less than planned volume, but actually exceeded my target OG gravity by 4 points... so I'll still have some good beer, just a bit less of it.
-sc