Say I want to mash and conduct most of the boil at pH 5.4, and reduce wort pH to 5.0 at the end. How do I calculate the acid addition, and just how late in the boil can I add it? (I’m thinking I want to keep pH up as long as possible to facilitate break and hop utilization.)
Kai might still have his calculation on his website kaiserbrew I think…
I’ve looked there and don’t think there’s anything on kettle acidification. Thanks though, I’ll look again.
EDIT nope still don’t see anything. I know somebody around here will help out before next brew day! 
That’s where I found it when I was brewing my Rube Goldberg German lager. It actually might be in my Rube Goldberg thread. My memory is that kettle acid did not enough to register as a thing for me. But I’m sure others will vehemently disagree.[emoji6]
I might have it on my tablet at home if the resident experts fail you.
That ain’t gonna happen! It’ll be raining knowledge around here. Whether I use it or not. Just wanna know.
What can come close is to use your mash pH calculator. Boiling doesn’t change your buffering…
Reworded, boiling doesn’t change MY buffering, not enough to matter.
That’s what I just started playing with. Calculate my desired mash pH, I get 0.15 ml/gal lactic 88. pH 5.0 needs 0.85. Subtract, the difference is 0.7, multiply that by kettle volume I’m trying to adjust and add that. Maybe?
Big Monk has the calculations embedded in the new version (7) of the low oxygen brewing spreadsheet, which is now in beta…
They have been in all our sheets.
Yup. I started doing it for Bryan in 2016. We have mineral acid and Sauergut calcs for mash, kettle, and 10 min pH reductions.
Where is this spreadsheet? I didn’t spot a link on LOB.
That’s the current (soon to be retired) version of the spreadsheet.
The proper addition is the amount of acid needed to take the MASH pH from the existing pH to the desired pH. The wort in the kettle has the same buffering as in the mash. Of course, this assumes that you have properly treated the sparging water to neutralize excess alkalinity.
PS: You can’t use this trick to change beer pH. Beer has more buffering and it takes more acid per tenth of pH unit reduction in beer than in wort.
So in my example in reply #7, the correct kettle addition would be simply 0.7ml total? (After my previous post it occurred to me that the buffering would remain constant. But i tried the LOB spreadsheet and it seems to confirm my initial estimate.)
I don’t think its going to take that much. I think it will be the difference in the acid rate times the mashing water volume, not kettle volume. But do check my assumptions with actual trials and measurements. I haven’t done so…yet.
Thanks, Martin. I also looked back at the thread Jim mentioned above, and it provides anecdotal evidence of people (Jim and AmandaK I think) getting the desired result with the larger amount of acid. I’ll have another data point to add (one way or the other) in two weeks.
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That’s the current (soon to be retired) version of the spreadsheet.
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That link no longer seems to work. Is there a new link for the spreadsheet? Thanks!