• Please visit and share your knowledge at our sister communities:
  • If you have not, please join our official Homebrewing Facebook Group!

    Homebrewing Facebook Group

A few words of warning regarding the use of Ca(OH)2 (Calcium Hydroxide) in mash water or in the mash

Homebrew Talk

Help Support Homebrew Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I'm no expert, but ISTM that your water report has to be wrong.
I think @Peebee is onto something re: low Alkalinity. In the 10s of hours I've spent reading blogs and materials on waters I believe I read that this might result in low pH. The only lab test I have conducted did tell me that my Total alkalinity was about 8 mg CaCO3/L - could this be the driver?

I sent a new water sample today to a lab to get all the stats, but that will take 2 weeks to come back...

Even then, I wonder why the slaked lime has made no impact, although I wasn't aware about how CO2 can impact it so it may be degraded and that's why it doesn't do anything... 😖
 
Last edited:
I think @Peebee is onto something re: low Alkalinity. In the 10s of hours I've spent reading blogs and materials on waters I believe I read that this might result in low pH. The only lab test I have conducted did tell me that my Total alkalinity was about 8 mg CaCO3/L - could this be the driver?

I sent a new water sample today to a lab to get all the stats, but that will take 2 weeks to come back...

Even then, I wonder why the slaked lime has made no impact, although I wasn't aware about how CO2 can impact it so it may be degraded and that's why it doesn't do anything... 😖
Nice job. The mystery deepens.

Even if you mashed with distilled water it should not be that low.

I'm not sure what could be in your tap water that would cause it to be that low. Massive amounts of calcium? You're getting it tested again, but maybe you could do a test mash with distilled water if available?

We've ruled out your other water additives now.

So that leaves grain -maybe a weird batch that's soured somehow?

Calibration solutions - maybe one is off/bad?

pH meter - somehow defective reading in between the calibration points? Or anything about the model that would mean it isn't good for measuring wort?

Other equipment - sample jar has some residue in it?

What else could we be missing and how can we test it?
 
Thank you
Very comprehensive.

Assuming the sample was cooled to 20C before pH reading. Edit I see it was cooled sufficiently.

You rinsed the pH meter off before using it and between tests?

If the reading hasn't been changed by temp or no rinse then it's either your water or the grains.

What's the pH of the water with the calibrated meter?

Have you tasted that pale malt ? Could it have started to sour or been contaminated with sour malt?
If it has it will taste " acidy" .
 
Nice job. The mystery deepens.

Even if you mashed with distilled water it should not be that low.

I'm not sure what could be in your tap water that would cause it to be that low. Massive amounts of calcium? You're getting it tested again, but maybe you could do a test mash with distilled water if available? I should be able to do this test, what pH should I expect?

We've ruled out your other water additives now.

So that leaves grain -maybe a weird batch that's soured somehow? No. I use this pale ale for a WIPA, NEIPA, Cream Ale, all 3 suffer the same issue, that's about 20 batches, so unless Weyermann in general is prone to be acidic, the issue is not isolated to my current batch of pale ale.

Calibration solutions - maybe one is off/bad? What are the odds, they are new, bought today for the experiment

pH meter - somehow defective reading in between the calibration points? Or anything about the model that would mean it isn't good for measuring wort? Maybe, Milwaukee 102 will take a month or so to get to Colombia

Other equipment - sample jar has some residue in it? All 4 samples were in different receptacles, I would say the odds would be very low.

What else could we be missing and how can we test it?

I'm not sure what could be in your tap water that would cause it to be that low. Massive amounts of calcium? You're getting it tested again, but maybe you could do a test mash with distilled water if available? I should be able to do this test, what pH should I expect?

We've ruled out your other water additives now.

So that leaves grain -maybe a weird batch that's soured somehow? No. I use this pale ale for a WIPA, NEIPA, Cream Ale, all 3 suffer the same issue, that's about 20 batches, so unless Weyermann in general is prone to be acidic, the issue is not isolated to my current batch of pale ale.

Calibration solutions - maybe one is off/bad? What are the odds, they are new, bought today for the experiment

pH meter - somehow defective reading in between the calibration points? Or anything about the model that would mean it isn't good for measuring wort? Maybe, Milwaukee 102 will take a month or so to get to Colombia

Other equipment - sample jar has some residue in it? All 4 samples were in different receptacles, I would say the odds would be very low.
 
Thank you
Very comprehensive.

Assuming the sample was cooled to 20C before pH reading. Edit I see it was cooled sufficiently.

You rinsed the pH meter off before using it and between tests?

If the reading hasn't been changed by temp or no rinse then it's either your water or the grains.

What's the pH of the water with the calibrated meter?

Have you tasted that pale malt ? Could it have started to sour or been contaminated with sour malt?
If it has it will taste " acidy" .
No, all 4 samples were measured at 25C.

Re: either water or grains: Grains: See response above, I don't think it is the grains, unless someone here has had pH issues isolated to weyermann.

pH of Water: 7.01

Water: If it were only one variable I would use the "solver" function in excel, can anyone think of a mineral combination in the source water that would lead to the observed 5.0 pH?
 
@sarandos25

The fact that you say pH issue has been occurring for all of your batches whatever style could mean that a whole sack has a problem.
Taste it, sour malt tastes acidic.
 
@sarandos25

The fact that you say pH issue has been occurring for all of your batches whatever style could mean that a whole sack has a problem.
Taste it, sour malt tastes acidic.
I haven't made myself clear. Those batches have been across several months, and I have purchased malt multiple times. Some batches in late 2023 were made with Pale Ale with a "Datum Produktion: 10.Jan.2023"; the stuff I have right now was bought in Q4'24 has a Produktion in 2024... i.e. the issue spans multiple harvests...

If anyone is wondering why now am I worrying about this... I have worried about it the whole time, but every time I think of something to try to fix it, it takes a couple of batches to test it out, e.g. bought a different pH meter, used baking soda, stopped using baking soda, started using slaked lime... once in a while a random batch would take place with decent pH (e.g. 5.1) I thought I had solved it, then for it to go back down, but I've run out of ideas for my trial and errors. As an FYI - all those beers have been decent, between 5.8 and 7.5% ABV, but I wonder if they could be better with a better pH and/or I could improve efficiency.
 
Last edited:
Okay not the malt then, otherwise there would be hundreds of posts with this issue.

Not sure if this question has been asked. How do your beers taste? and has anyone else tasted them and noted any " strangeness ".

Next time you open one of the beers or tap one can you check the beer pH?
 
I'm not sure what could be in your tap water that would cause it to be that low. Massive amounts of calcium? You're getting it tested again, but maybe you could do a test mash with distilled water if available? I should be able to do this test, what pH should I expect?

We've ruled out your other water additives now.

So that leaves grain -maybe a weird batch that's soured somehow? No. I use this pale ale for a WIPA, NEIPA, Cream Ale, all 3 suffer the same issue, that's about 20 batches, so unless Weyermann in general is prone to be acidic, the issue is not isolated to my current batch of pale ale.

Calibration solutions - maybe one is off/bad? What are the odds, they are new, bought today for the experiment

pH meter - somehow defective reading in between the calibration points? Or anything about the model that would mean it isn't good for measuring wort? Maybe, Milwaukee 102 will take a month or so to get to Colombia

Other equipment - sample jar has some residue in it? All 4 samples were in different receptacles, I would say the odds would be very low.

Distilled water is basically all 0s for mineral content, so plug that into your brewing software. I'd expect the pH to come out a lot higher than 5 in a light base malt mash with distilled water if the water was the issue.

If you've used this well-known grain brand from several different lots over the years and have still seen the issue, then it doesn't seem like it would be the malt.

New calibration solutions today would mean that the old ones were also bad, so unlikely to be the culprit as long as they aren't expired or dodgy.

We can rule out the sample jars as long as they all don't have some kind of highly acidic residue.

If the distilled water test comes out low pH, then maybe the meter is bad....

This is an interesting exercise from my point of view to troubleshoot, but I'm sure it is very frustrating on your end :bigmug:
 
For pH calibration, I'd be sure to rinse the meter probe in distilled water between measurements and dry it off as much as possible as well. For ultimate measurement have 2 vials of cal fluid - go from the rinse / dry to the first fluid, swirl and then go to the next one. It gets silly at some point but ensures totally minimal carryover if you get desperate. And only if you do as more mundane methods should still be enough and not this far off (if off at all).
 
I think @Peebee is onto something re: low Alkalinity.
I had better preen my best feathers for a bit of strutting about ...

The mystery deepens. ...
Not really. But I'd agree the "mystery" perhaps needs digging out of its shallow grave?

Okay, enough talking in riddles, and trying to take credit for coming up with a "novel" idea. All I've done is resurrected some dusty features in "Bru'n Water" ... "Add Sparging Mineral Additions to the Mash" and, more importantly, "Add Hardness Minerals to the Kettle"... There were reasons for these features, but they appear to have been forgotten because I had to come up with my own reasons to use them (I couldn't find any guidance).

Lots of speculation about the causes of @sarandos25's problem: pH? Unusual grain? But pH has a somewhat tentative connection with what's being done here (the reason I've just got myself a load of less accurate brewing pH indicator papers to use instead of my meter). Different "calculators" are going to arrive at different pH predictions, and, rather handily, the reasons are grain! Remember who is the "Original Poster" (or Original Post's author ... I can never figure out what "OP" stands for?), @Silver_Is_Money (I was only chatting to him a few weeks ago, so he knows why I'm going off on one here!). Here's a thread he's in, relevant to what I've just said: https://www.homebrewtalk.com/thread...iffe-and-spencer-in-2018.702832/#post-9318458

("Quasi-empirical" ... one of his favorite words? One of mine too now I've Googled what "quasi" means ... it's what I do! "Apparently but not really" 😁 ).

So, I don't believe these pH, grain, etc. explanations here, I reckon it's to do with @sarandos25's use of highly mineralised brewing water (Calcium at 120ppm ... more like I'd do being a Brit brewing "traditional" British style beer). All that Calcium and tap water alkalinity at a low starting point (the latter also possibly affecting how the brewer may react), that's where I see the problem lies (Calcium + Malt grains = pH going down!) .

And of course ... I could be wrong!



The last comment is because this topic is dangerously close to the topic that has recently got me thrown off the UK "sister" forum! The UK "THBF". And it was me reporting the infringement of forum rules! So, I'm being careful here, though I do trust the moderators here to handle things "differently".
 
I had better preen my best feathers for a bit of strutting about ...


Not really. But I'd agree the "mystery" perhaps needs digging out of its shallow grave?

Okay, enough talking in riddles, and trying to take credit for coming up with a "novel" idea. All I've done is resurrected some dusty features in "Bru'n Water" ... "Add Sparging Mineral Additions to the Mash" and, more importantly, "Add Hardness Minerals to the Kettle"... There were reasons for these features, but they appear to have been forgotten because I had to come up with my own reasons to use them (I couldn't find any guidance).

Lots of speculation about the causes of @sarandos25's problem: pH? Unusual grain? But pH has a somewhat tentative connection with what's being done here (the reason I've just got myself a load of less accurate brewing pH indicator papers to use instead of my meter). Different "calculators" are going to arrive at different pH predictions, and, rather handily, the reasons are grain! Remember who is the "Original Poster" (or Original Post's author ... I can never figure out what "OP" stands for?), @Silver_Is_Money (I was only chatting to him a few weeks ago, so he knows why I'm going off on one here!). Here's a thread he's in, relevant to what I've just said: https://www.homebrewtalk.com/thread...iffe-and-spencer-in-2018.702832/#post-9318458

("Quasi-empirical" ... one of his favorite words? One of mine too now I've Googled what "quasi" means ... it's what I do! "Apparently but not really" 😁 ).

So, I don't believe these pH, grain, etc. explanations here, I reckon it's to do with @sarandos25's use of highly mineralised brewing water (Calcium at 120ppm ... more like I'd do being a Brit brewing "traditional" British style beer). All that Calcium and tap water alkalinity at a low starting point (the latter also possibly affecting how the brewer may react), that's where I see the problem lies (Calcium + Malt grains = pH going down!) .

And of course ... I could be wrong!



The last comment is because this topic is dangerously close to the topic that has recently got me thrown off the UK "sister" forum! The UK "THBF". And it was me reporting the infringement of forum rules! So, I'm being careful here, though I do trust the moderators here to handle things "differently".


If the water testing was correct there is low Ca in the brewing water.
 
OK... really excited to share the results; curious to see the reactions to them:

Test:
500gr Weyermann Pale Ale
1.5 liters of source tap water
0 salt additions

pH Calibration
View attachment 866412

View attachment 866413

Additional visual validation:
Pale ale
View attachment 866414
Mashed at 67 C for 60 Minutes
View attachment 866416

Now the interesting things:

Mash pH 20' measured at 25 C
View attachment 866418

Mash pH 30' measured at 25 C

View attachment 866419

Mash pH 45' measured at 25 C
View attachment 866420

Mash pH 60' measured at 25 C
View attachment 866421

Based on the calc the pH should be clocking in at 5.7...

View attachment 866422

View attachment 866423


Help please!!

The proper solutions to calibrate that meter are 6.86 pH, 4.0 pH and 9.18 pH.

It looks like you're using a 4 pH and 7 pH.

You'll also want to do the correct calibration sequence of 6.86 -> 4.0 -> 9.18.

According to the instruction sheet you'll need to use all three solutions to get the most accurate results.

The one point calibration isn't appropriate for mash and the two point uses 4.0 -> 9.18 solutions.

Try the proper calibration solutions with the three point calibration. That should bring the pH meter within the appropriate range of your actual mash pH.

1736525136745.png


Here's some instructions:

 
Last edited:
@Peebee

The mini mash by @sarandos25 used tap water with values generated two ways


Water Test Results from Brewlab kit
Ca <5 ppm
Mg 2.4 ppm
Na 40 ppm
Cl 30 ppm
SO 25 ppm
Alkalinity CaCO3 20 ppm
Alkalinity HCO3 24 ppm

Independent Professional Lab Test
Total Alkalinity CaCO3 8 ppm
Alkalinity Carbonate (CaCo3) 0 ppm
Alkalinity Bicarbonate (aCaCo3) 8 ppm
Total Hardness (CaCo3) 0 ppm
Calcium Hardness (CaCo3) 0 ppm


There were no salts added to the mash see top of post 58 and the pH was measured at 4.9 to 5.02.

Noted since your post that the meter may have been calibrated wrong.

I still wonder how does all of the beer taste from many batches?
 
If the water testing was correct there is low Ca in the brewing water.
Best answered by @sarandos25, but I assumed the "brewing water" (source water) was low (2ppm), my reply was referring to the target profile (120ppm). And ... ahhh!

Thanks very much @marc1. Eee, it's not 'arf nice having someone politely pointing out an error! I've completely skipped an important step. If using the "Add Hardness Minerals to the Kettle" the "source water" had better contain all the salts for the mash, because there's no obvious way to add them in "Bru'n Water" now (unless anyone can tell me differently?).

Sorry: Another big graphic! But I don't think I've forgotten anything this time:
1736539141787.png


2.03g gypsum, 0.87g lime, added to water before mash (so it appears on "Existing Water Profile" above). I opened another instance of Bru'n Water to calculate this. Not ideal, confusing as hell, but it gets everything setup right. Note you don't have to put up with "User Custom" as the Water Profile name, Martin allows them to be modified. I've put in @sarandos25's tap water to further illustrate this, and show what those two additions above have done.

"Add Sparging Mineral Additions to the Mash" and "Add Hardness Minerals to the Kettle" options have been enabled, so the Calcium and Magnesium salts turn "amber" telling you to add to sparge/boiler. Doesn't do same for "Common Salt", but you can chuck it in the boiler/sparge if you want.

Other salts have been altered so "Overall Finished Water Profile" adds up to the "Desired Water Profile". Acid addition is only to get pH5.4 which seems more reasonable for this recipe. Note I've effectively fooled Bru'n Water into adding acid and alkalinity at the same time (the alkalinity was added as part of the "Existing Water Profile"); this is not good, but is getting the job done.

There's an error showing, "Can't add all minerals to ...". This appears to be a bug 'cos of all the "undocumented" stuff I'm asking it to do?



There go: Completely over the top! Well, that's what I do!
 
@Peebee
I think the point is the base water is pretty bland and used in a mini mash with NO salts added to the tap water the measured pH is still lower than predicted.
I'm still working with the full-size batch @sarandos25's original post laid out, not the mini-mash stuff.

This path is what I'm having to take myself, because I couldn't get any valid answers from forum communities. For me, it's very new and I've proven I'm apt to make the odd slipup trying to describe it. But coming here (to this forum) and immediately finding someone in the same boat, I couldn't resist trying to help out.

The Problem:
Having a water supply with a very low TDS (Calcium ions <35ppm, and Alkalinity <20ppm as CaCO3 ... actual maximums not yet determined) and attempting to create a highly mineralised brewing water (Calcium >120ppm). Attempts end up with an unexpectedly low Mash pH (<pH5.2, even <pH5.0).

Reasons?
The Calcium ions react with constituents in the malt to force the pH down. Combined with (in my case) a resistance to sufficiently combat the lowering pH with additions of yet more "alkaline" salts (because that's what we were always told ... by the vast majority who must brew with high TDS waters ... i.e. adding Alkalinity salts = Bad!). In the case of using Calcium alkalinity additions (like Calcium Hydroxide, aka "Lime") the extra Calcium exacerbates the problem (a warning that's in the 2020 original postings of this very thread).



I'll take a look at "rescaling" to match the "mini-mash" experiments, but I don't predict it'll be necessary. I can foresee a much bigger problem if those using RO Water develop a taste for "old world" highly mineralised brewing waters, but I don't think there is any chance of that in the near future.
 
This was the working out of Calcium and Alkalinity amounts for the mash water. The amounts should be added directly to the "Water Report Input" of the "primary iteration" of Bru'n Water:

1736590772444.png


2.1 grams of gypsum, 0.9 grams of Lime. Added to the 29L mash water. And the component parts added virtually to the "Water Report Input" of the Main (Primary) instance of Bru'n Water (so it isn't interferred with when enabling the "Add Hardness Minerals to the Kettle" option. The pH displayed for these working outs is immaterial.

32-35mg/L of Calcium ions was derived from Web searches as the minimum calcium level for a healthy Mash. I would have preferred a more definitive quantity with references.
 
I'm with @AdjunctBrewer on calibration, although, maybe in this case, it may not be vital to use three point calibration. What is important is the first calibration be done at pH 7, because it is centre scale. That adjustment moves the entire scale sideways if we think in an analogue way. The adjustment at pH 4 then adjusts the gain within the instrument, which in analogue terms widens or narrows the range of the readout.

I'm in the camp that believes only exceptional recipes will require alkalinity in a mash with soft water to brew most darker beers.

Good luck, you are making great progress.
 
I catch up eventually!

Mini-mash: Yeap, confirm pH is calculated in Bru'n Water as 5.70. Actually appears to be 5.02 in practice. That is nothing to do with what I'm messing about with, it would require (theoretically - if there's enough "stuff" in the malt to react with) Calcium ions to go up by about 298mg/l to achieve that (according to Bru'n Water). Seems very (very³?) unlikely.

Erm ... well, I've nothing more to add?
 
I catch up eventually!

Mini-mash: Yeap, confirm pH is calculated in Bru'n Water as 5.70. Actually appears to be 5.02 in practice. That is nothing to do with what I'm messing about with, it would require (theoretically - if there's enough "stuff" in the malt to react with) Calcium ions to go up by about 298mg/l to achieve that (according to Bru'n Water). Seems very (very³?) unlikely.

Erm ... well, I've nothing more to add?
My money is on a measurement generated wrong value. The new pH meter and retest should clarify.
 
My money is on a measurement generated wrong value. The new pH meter and retest should clarify.
I wondered that last night after posting (and re-reading Cire's posts); it's a long time (years) since those "pen testers" required such care calibrating. Now-a-days the testers are just dropped into a buffer solution, it recognised the buffer, and calibrates accordingly? The probes on those pens have a finite life (about 6-18monthes) whether you use them or not. So, are any of those old-style 3-point calibrated pen-testers still in-date?

If it's over a year old, whether or not it holds calibration longer than a few minutes, bin it! A "new pH tester" is in order!
 
I wondered that last night after posting (and re-reading Cire's posts); it's a long time (years) since those "pen testers" required such care calibrating. Now-a-days the testers are just dropped into a buffer solution, it recognised the buffer, and calibrates accordingly? The probes on those pens have a finite life (about 6-18monthes) whether you use them or not. So, are any of those old-style 3-point calibrated pen-testers still in-date?

If it's over a year old, whether or not it holds calibration longer than a few minutes, bin it! A "new pH tester" is in order!
He's got a Milwaukee on order.
I've got two of those cheapies calibrate and store in the correct medium. Both working fine and well over 2 years old.
 
First link Google returned from searching: "ph probe lifespan"

pH Probe Replacement

Tell people yours' are okay after two years, and they will continue using them for three, whatever state they are in.

I'm stopping using then (unless for "investigation" work). The plastic single-use strips are more than adequate. Not precise enough? Try reading some of @Silver_Is_Money's or @ajdelange's threads on Mash pH ... that cures you of having too fanciful ideas about pH! The ones I've purchased for beer-making (but perhaps not for "researching" pH):

Beer pH Indicator Strips
 

Latest posts

Back
Top