First 2 step Mash on Bert Grant's Perfect Porter - how do you do it right?

I have done some pretty good and cosistent brews and would like to up the degree of difficulty a hair.

I plan on attempting Bert Grant's Perfect Porter tribute. The recipe calls for a 2 step mash and gives the following schedule:

Temperature Mash, 2 Step, Full Body
Step Time Name Description Step Temp
20 min Protein Rest Add 11.45 qt of water at 135.0 F 127.0 F
30 min Saccharification Heat to 158.0 F over 15 min 158.0 F
10 min Mash Out Heat to 168.0 F over 10 min 168.0 F


How much water would I start with? I would assume that since my total grain bill is 9.8 lbs and my preboil volume is 7.20 GL, I would need to begin my mash with 12.74 qts of water (using 1.3 qts per lb of Grain)

Would I take the addition of 11.45 qt 127 F of water at 135 F from the sparge water, then sparge with 2.4 gallons (assuming 1.25 gallons absorbed) ofwater to make up the 7.2 Gallons of water?

If it matters I am using and 8 gallon MLT with a false bottom.

Thanks all!

Well...it looks like he's using a HERMS or RIMS system to heat his mash, so you won't be able to duplicate the recipe exactly.

Use this http://www.brewersfriend.com/mash/

Use 127 as your taget temp and 1qt/lb. Then at the bottom where it calculated, type in the next temp steps you need to hit. It will tell you how much boiling water needs to be added to the mash to hit your temp. Then, when your mash is done, figure out how much water you've got in your mash (minus your grain absorbtion) and add enough sparge water to hit your pre-boil volume.

Got it- I'll use my pot without the false bottom then transfer to the larger pot with the false bottom for sparging- Thanks for the help!