Tomorrow I am gong to try a 10 gallon batch of Surly Abrasive.
I will have 36 lbs of grain. At 1.5 qt/lb, I will get about 10 gallons on my first runoff if I have .1 gallon absorbtion per lb. Assuming I get 10 gallons out of the first runnings, it looks like I would only need about 1.5 gallons more to complete a 60 minute boil.
This will not allow me to be anywhere near a 50/50 mix from first and second runnings. Should I change something?
Not much you can do when using that large of a grain bill.
With MashWater
http://gnipsel.com/beer/software/beer-software.html
, I get 13.5g mash water. 0 Mash out. And 2.07g sparge volume for 11g to the boil pot.
You could go 1.25qt/lb. 11.25g mash water, 0 mash out, 4.32g sparge volume for 11g in the pot.
Grain absorption is ~4.32 gallons. Add 1/2 gallon to the sparge water if you want to be at 11.5 pre boil.
Because of the lack of sparge water, expect your efficiency to be less then normal. Possibly 10% or more.
You could also sparge more and boil on a second heat source. Friends burner or kitchen stove to capture more sugar.
