I did a partial mash Robust Porter the other day. I use Beersmith to calculate volumes, temps, etc. for my 2 gallon cooler partial mash system.
Here's my problem: my mash tun was full before I got all the mash water in.
4.85 lbs of grain
1.25qt/lb = 6.06 qt
Tun volume required = 1.89 gal
However, I could only get 5 qts of water in my 2 gallon cooler (with the 4.85 lbs of grain. this should fill 1.63 gal). As a result, my temps were all off and I had no room to add boiling water to correct the temps.
Why would 1.63 gallons fill a 2 gallon cooler?
I use a grain bag, so there's really no dead space in the mash tun. Also, I reserve the right to have done something really stupid, like mis-counting the amount of water added, but I don't think that's the case.
(This is my first thread, but I've lurked here for a while. I've learned a TON of stuff from this forum, so thanks to everyone.)