I have done a few extract kit beers and now a few partial mashes. I am starting the process of ramping up to all-grain.
In many online "brewing calculators", such as this mash water chemistry tool by Beersmith, they indicate that the total water volume is different than the mash water volume:
I can understand that total water volume might be equal to mash volume plus sparge water volume, but is any other water (besides the sparge) added to the "total" at any point in the all grain brewing process? Why is it added, and when?