Modifying water for double mash

[OldGoatBrewing]

All, I am doing a double mash this week for a 10% barleywine. I have done this a few times now with good results. However, I recently moved to a new area and have started modifying my water with Epsom Salt, Calcium Chloride and Gypsum. I use EZ Water Calculator to determine the amounts of salts. However, this is the first double mash I have done since using salts to modify PH. The question is, should I calculate for the entire grain bill (18lbs) or should I calculate for 9lbs at a time. My thoughts: If I calculate for the entire grain bill, I will overshoot my PH on the first mash and maybe hit the mark on the second. If I calculate for 1/2 the bill at a time, I will hit the PH on the first mash, but will have to take a PH reading between mashes, recalculate for the 2nd mash. Does either of these sound right. I am definitely not a chemist, but I am hoping someone out there has dealt with this.

 

[eric19312]

Interesting question @maxbrew . But first I don't think it is necessary on this HomeBrewTalk to post same question in two places. I am not sure if anyone except the moderators focus on just a few forums, I think most of us just look for something new.

Chris Colby over at Beer and Wind Journal has written a number of articles about something he calls reiterated mashing which may be what you mean by double mashing. Basically using wort as your brewing liquor for the second mash. In this article
https://beerandwinejournal.com/reiterated-mashing-2/#more-1140
he mentions in the second mash you need to replace the calcium that was consumed by your first mash. I think the sulfate and chloride make it through the mash but some calcium is consumed in the mash. You might want to back off on the epsom salt and just use gypsum for extra calcium. Then split the gypsum between first and second mashes. Good luck and let us know what you end up doing and how it works out.

 

[OldGoatBrewing]

Great...thanks eric19312, I will read that article tonight and learn something new. I appreciate your response and the time you put into it. I will try to update after brewday.

 

[deadwolfbones]

I did a big stout using Chris Colby's technique and wrote about the process here: https://brew4fun.wordpress.com/2019/01/13/polygyle-party/

I didn't add any extra salts to the second mash and it came out great.

 

[OldGoatBrewing]

Thanks deadwolfbones (interesting handle). I have your blog pulled up and will read it tonight! I appreciate it. Looks like a really good, in-depth write-up. Looking forward to it.