Water volume for mineral additions

[whiterussian]

I just finished listening to the Waterganza shows (all 4 of them), and there is just one point which I am still confused about. Jamil and John talk about having separate mineral additions for the mash and for the sparge, but which volume of water do you target overall, pre- or post-boil? If it's pre-boil, then wouldn't you have an excess of minerals since part of the water boils off? I do 7 gallon boils in my system and I end up with about 6 gallons post-boil, and of that about 5.25-5.5 go into the fermenter. So should calculate the total minerals amount for 7 gallons or 6 gallons?

[Brewchief]

That's a good question; though by John's own admission there is an awful lot of arm waving with mineral additions. Such so, I'd feel confident that the difference between 6 and 7 gallons (<15%) wouldn't warrant extra concern in most cases (ever, in mine).

Pretty sure I read the answer to this somewhere, but didn't care enough to note. I hope your question gets answered; but if not, I'd relax, not worry and have a homebrew!

[whiterussian]

Actually, the answer was provided at the very end of Water show #4. Basically, you should target pre-boil volume and not worry about minerals concentrating during boil-off, because back in the day the brewers just used the water they had and so their boiling concentrated the minerals too.

[DCBC]

Sorry for resurrecting this old thread, but I had this question a while back as well. I emailed Jamil about it and he told me that kettle additions (or sparge additions) should be calculated on post boil volume. I don't remember this question being addressed in the Waterganza, but it has been some time since I have listened to it. I understand the part of about traditional water profiles being concentrated, but this is the answer I got from him via email a few months after the shows.

In my setup, I add minerals to the mash, assume that they are equally distributed by the end of it and that a % of the minerals will be absorbed along with whatever % of water is absorbed by the grain (so the mineral ppm stays the same in the first runnings even with the smaller volume versus strike water going in). I take the volume of my first runnings and subract that from my post boil volume and use that amount to calculate my kettle mineral additions.