Beersmith Water Volume Calculations

I have a few questions about how Beersmith calculates mash water and sparge water to result in the end result batch size.

For example. When reviewing a recipe for Yoopers Dead Guy Ale clone (12.5 # grain), the total step-mash (18.75 qt then 6.25 qt) volume is 6.25 gallons (12.5 # grain) and the sparge water is 2.21 gallons.
If figuring .12 gallons absorbtion per pound of grain, the post-mash volume (-1.5 gallon) would be 4.75 gallons.

4.75 mashed gallons + 2.21 sparged runnings = 6.96 pre-boil gallons.

If figuring .11 gallon loss per hour, the post-boil volume for one hour is 6.96*.11 or .77 gallons (3/4 gal) lost to evaporation resulting in 6.19 gallons post-boil.

Considering the target volume is 5.25 gallons, where did the other 0.94 (let's call it 1 gallon) of water go? Is it lost to trub?
What else consumes water?

Also, I mash in a bag (voile material) so there is very little or no trub in the boil kettle. The mash runnings are very clean. Considering I mash in a bag and have very clean runnings should I adjust for zero trub in the kettle OR is the trub loss assumed to be in the fermenter?

I am confused .. please help.

Hi,
  It depends on both your equipment and recipe settings, but if you want to understand how the basic water calculation is performed take a close look at the water needed tool - it closely mirrors what is going on in within the recipe calculations.  If you enter your numbers here you should be able to trace through the calculations.

There is a default calculation that allows for 4% loss during cooling. I understand that this calculation assumes that there is still evaporation taking place while the hot wort is cooling. 4% of your .96 gal would account for .0.247 call it 0.25 gal bringing your missing water down to 0.71 gal. I guess that much loss could be split up between the boil trub and what you can't recover after the sparge.