So! I have done some further research and come up with some figures, just want to know if they're OK...
An issue I do have is that I haven't yet done an hour boil to get my boil off rate, I could do this before I brew if it would really help.
So with 8.90 lb of grain, with a ratio of 1.25:1 qt/lb, that gives me a strike water volume of 11.125 quarts (2.8 US gallons, 10.6 Liters).
Using the suggestion of .1gal/lb absorption, that suggests that the mash will absorb .90 gallons of water, leaving me with 1.9 US gallons from first runnings.
Should i then batch sparge, maybe twice, with a total of 5 US gallons of water in order to reach a preboil volume of 7 Gallons?
From what I read on Denny's website, I would perform the hour mash and vorlauf, and then before draining, add 2.5 US Gallons, stir, and drain completely, add the next 2.5 US gallons stir and drain, and then get on with the boil. Does this sound reasonable or have I made a big mistake somewhere?!
Cheers
Denny has changed his (my) method since writing that! You know I'm lazy and I decided that extra addition was too much work! Now I mash thinner...usually between 1.65-75 qt./lb. That takes care of having to add extra water. It also increased my efficiency! Then I usually measure how much mash runoff I get in the kettle and subtract that from the amount I want to boil (usually 7-7.5 gal. for a 5 gal. batch). The answer I get is how much sparge water to use. EASY! I heat that sparge water to 185-195F, stir it in, vorlauf and runoff...I don't let it sit before the runoff. Any questions?