First off I must confess I am math challenged. With this in mind I will describe my last brew day I am using ½ barrel Sanke kegs and taking volume measurements by marking my mash paddle from the center of the domed bottom of the keg. I first measure the water going into HLT for my mash water I add 11 gallons and mark this level on my mash paddle the water is 60 F. For my mash I heat 7 gallons of water to 165 in my mash tun for a 10 gallon batch of beer (21 lbs of grain) mash at 154. I sparge with 170 f water to collect about 11 gallons of wort at 132 F the gravity is 1.040 (adjusted to 1.053 at 60 F) it’s about 1 inch over the 11 gallon mark I made on my paddle earlier (I collected more for my estimate of thermal expansion) I boil the wort for 2 hours (2 hours because I'm using Pilsner malt normally I boil for 1 hour). I end up with 8 gallons of 1.070 wort 2 gallons short and .010 over my target OG. Does anyone have a source for thermal expansion and boil off rates, like I said I am using Sanke kegs as are a lot of other folks out there. I figured I would end up with 10 gallons by starting with 11 but I ended up with only 8 I left only 1 quart behind in the boil kettle. So either my guess on thermal expansion is off or boil off was estimated too low. I am using Beer smith software, don’t know enough about the software maybe I can plug numbers in there?