So I'm on to my second home brew very soon and have sorted most things out that I got wrong last time. Unfortunately last time I didn't record how much water I lose during the mash and boil etc... So my question is what do I do when it comes to water quantity with my brew if I don't know how much will boil off? My Idea is this: Mash In with 6 gallons like the recipe states, then when it comes to the sparge which says use an additional 6.5 gallons which will bring it to 12.5 gallons in total with an end result of 5 gallons... Instead of this I was thinking maybe sparge with 4 then just towards the end of the boil before I put the wort chiller in I'll take a gravity reading and see how much water I need to top the wort up with. The reason for this Is I don't want to have a brew that has to much water in, is this a good idea? Or do I top it up with water before transferring to fermenting bucket or do I just use what the recipe says? Also should the water I use to top up be the same temp as the wort I'm putting it into?