Corcis wrote:Slothrob: The mash thickness experiment may be reinventing the wheel, but I like to do that sort of thing to figure out how things work.
I understand, because I do the same thing. I'm a biochemist and I long ago learned to reproduce peoples experiments before accepting them as fact.
One nice thing about double milling is that it allows you to see what role crush is playing in your efficiency loss, but significantly reduces the chance of shredding the husks that a tight gap has the potential to create. I mill tight but condition the grain to avoid that potential problem, but it's good to keep it as simple as possible in the beginning.
Your thermometer is probably about 2F high, depending on your altitude, but the deviation isn't always linear. Checking that it also reads 0F (or probably 2F) in a glass of crushed ice just covered in water is another good calibration check. Even then, thermometers can be off in the middle of their range, especially mechanical ones, so it's good to have a reference lab thermometer to check the calibration at mash temperatures. For now, I'd probably just assume 2F high, or whatever is appropriate to your altitude.
