Adjusting RO water pH to 5.5 before mashing

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J.Miller

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Hello,
Some homebrew recipes include adjusting brewing water to 5.5 pH before adding mineral salts and mashing. I am asking those of you that do this, how many hours or days (or immediately) ahead of mashing do you adjust pH?
I use RO water and wonder if my acid addition into brewing water needs a longer time to stabilize than what I typically do.
I add phosphoric acid (the full volume predicted by Bru'n Water to my total volume of mash and batch sparge water, mix with a mash paddle, and separate the sparge volume before mineral additions and heating the mash water.
I use an Apera PH 60 pen meter.
I'm concerned that if there is a lag time in stabilization, the pH reading may be high, resulting in addition of more acid to lower the pH, but result in a too low actual pH during brewing.
To check this, I have incrementally added acid to 5 gallons of RO brewing water, stirred, and took pH readings over a number of hours time before adding more acid, and found that the pH readings increase several tenths of pH and stabilize over several hours. Now I wonder if my pH meter is faulty.
Your comments please. Thanks.
Jeff
 
With adequate mixing, the neutralization reaction is quite rapid.

There are two phenomena I can see as "potentially" being at work here:

1) The classic error in pH reading known (per AJ deLange) as "stirring error" will assuredly yield a false low pH reading. And the "stability indicators" on pH meters are notoriously ridiculously quick in signaling stability, particularly when not all that many ions are present (such as for pH 5.5), and it is best to leave the probe sit undisturbed by any degree of stirring or motion for a full minute (or more) before reading the pH. Stirring falsely drives the pH reading down.

2) Particularly in higher Alkalinity situations Phosphoric Acid reacts not only with Alkalinity, but also with Calcium, complexing with it, forming the phosphate mineral called 'Apatite', and in the process diminishing the amount of available Phosphoric Acid in solution, which over time would be seen a a rise in pH due to the lessened presence of H+ ions. (credit for this observation also goes to AJ deLange)

Try using a different acid plus take heed of #1 above and see if the very same pH rise is observed over time.

I recall seeing a photo taken by a brewer in the UK showing so much Calcium Apitate dropping out after adding Phosphoric Acid that his water was cloudy white, and it coated his kettles electric heating element. He noted that with other acids this never occurred. Particularly with higher Alkalinity combined with Ca++ rich water, Phosphoric Acid should never be used.
 
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Lastly, there could be an issue with the pH probe and/or calibration leading to poor stability.
 
Some homebrew recipes include adjusting brewing water to 5.5 pH before adding mineral salts and mashing.

Do they? Those would be bad recipes. 5.5 is a good mash pH target, but to state a starting strike water pH of 5.5 (or any value) is irrelevant. What matters is the alkalinity and calcium/magnesium content, and the acid contributions and buffering capacity of the grain bill. IOW, there's no way that specifying a starting strike water pH or 5.5 (or anything else) does anything meaningful. Sparge water, OTOH, is another story. Are those recipes perhaps referring to 5.5. pH for sparge water, to avoid extracting excess tannins during the sparge?

I add phosphoric acid (the full volume predicted by Bru'n Water to my total volume of mash and batch sparge water, mix with a mash paddle, and separate the sparge volume before mineral additions and heating the mash water.

As long as you're using a good model to predict the mash pH, and assuming your sparge water is in a good range after the en masse mass acid addition, that's a fine strategy.

I'm concerned that if there is a lag time in stabilization, the pH reading may be high, resulting in addition of more acid to lower the pH, but result in a too low actual pH during brewing.

If you're talking about water (and not the mash itself)... Add acid. Stir. It should be "stable" in practically no time.
 
Thanks for replies!
Silver... pH readings taken about 1 minute after stirring and meter immersion. pH readings in RO water at 67° F, original pH at 6.4.
Vike, Gordon Strong weissbier recipe. He includes using phosphoric acid.

Jeff
 
If it's RO water it should not take much acid at all to change the pH, because there's nothing to buffer it.

What exactly does the recipe say to do for the water treatment? There's possibly a misunderstanding about it.
 
Vike, Gordon Strong weissbier recipe. He includes using phosphoric acid.

Yeah, that's Gordon's "RO water plus acid to 5.5 pH plus a teaspoon of CaCl2 (or whatever)" method. He "gets away" with that for his recipes, his strike water to grain ratios, and his batch sizes, because he doesn't include the dark grains (when applicable) in the main mash. So his (mashed) grain bills are all pretty similar.

But start with something other than RO (or distilled), mash at a different thickness, or mash all the grains, and it becomes more problematic.

Also, moving RO/Distilled water to 5.5 pH takes a minuscule amount of acid, as @marc1 mentioned. Like less acid than you can probably accurately measure. And it serves no purpose.
 
Yeah, that's Gordon's "RO water plus acid to 5.5 pH plus a teaspoon of CaCl2 (or whatever)" method. He "gets away" with that for his recipes, his strike water to grain ratios, and his batch sizes, because he doesn't include the dark grains (when applicable) in the main mash. So his (mashed) grain bills are all pretty similar.

But start with something other than RO (or distilled), mash at a different thickness, or mash all the grains, and it becomes more problematic.

Also, moving RO/Distilled water to 5.5 pH takes a minuscule amount of acid, as @marc1 mentioned. Like less acid than you can probably accurately measure. And it serves no purpose.

It's been a while since I've read his books. The way I remembered it, he added roasted grains late, and used teaspoon type measurements of salts. I thought he also did a standard volume measurement of acid for his system rather than using a pH meter on the RO source water.

Adjusting the pH on the source water with a pH meter seems like a big step backwards on his simplification of his specific brewing process.

It obviously works for him, but you'll have to do some trials on your own if you want to get this method dialed in for your system.

-------------------------------------------------

Anyway, back to the original issue:

- are you sure your water is RO? Have you checked with a TDS meter to verify? I've gotten some bad water from those dispensing machines.
- is your pH meter calibrated every time before use?

Also, I just noticed that you add the acid addition prediction from BrunWater to all of your (RO) water, then split it for mash and sparge? Isn't the acid addition supposed to be separated? One for the mash, to achieve the desired estimated mash pH, and one for the sparge, if necessary, to neutralize alkalinity (shouldn't be necessary for RO)?
 
Unless I simply missed it, the first post to this thread made no mention that the source water was from RO. It takes less than a drop of acid to move good RO to (or below) pH 5.5. This for normal homebrewing water quantities...

Simply leaving RO openly exposed to air overnight will likely bring it down to pH 5.8.

With so few ions in solution, getting a reliable read of good RO waters pH is a difficult task. With so little Alkalinity it is a waste of time to acidify it.

As @VikeMan stated, acidification to a target pH is strictly oriented towards sparge water. But for RO this is a moot point. Once Alkalinity falls to or below 25 mg/L (ppm) it is a moot point. Some brewing researchers of yore (meaning pre the homebrewing as well as the microbrewing era, and thus with their research commercial brewing oriented) even went so far as to say that for Sparge water once Alkalinity is below 50 mg/L it is a moot point.

Only homebrewers (and microbrewers spawned by them) speak (in error as it is) of zeroing Alkalinity. But that requires acidifying to (at or or below) a pH of 4.3.
 
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Hello,
Some homebrew recipes include adjusting brewing water to 5.5 pH before adding mineral salts and mashing. I am asking those of you that do this, how many hours or days (or immediately) ahead of mashing do you adjust pH?
I use RO water and wonder if my acid addition into brewing water needs a longer time to stabilize than what I typically do.
I add phosphoric acid (the full volume predicted by Bru'n Water to my total volume of mash and batch sparge water, mix with a mash paddle, and separate the sparge volume before mineral additions and heating the mash water.
I use an Apera PH 60 pen meter.
I'm concerned that if there is a lag time in stabilization, the pH reading may be high, resulting in addition of more acid to lower the pH, but result in a too low actual pH during brewing.
To check this, I have incrementally added acid to 5 gallons of RO brewing water, stirred, and took pH readings over a number of hours time before adding more acid, and found that the pH readings increase several tenths of pH and stabilize over several hours. Now I wonder if my pH meter is faulty.
Your comments please. Thanks.
Jeff

Unless I simply missed it, the first post to this thread made no mention that the source water was from RO. It takes less than a drop of acid to move good RO to (or below) pH 5.5. This for normal homebrewing water quantities...

Simply leaving RO openly exposed to air overnight will likely bring it down to pH 5.8.

With so few ions in solution, getting a reliable read of good RO waters pH is a difficult task. With so little Alkalinity it is a waste of time to acidify it.

As @VikeMan stated, acidification to a target pH is strictly oriented towards sparge water. But for RO this is a moot point. Once Alkalinity falls to or below 25 mg/L (ppm) it is a moot point. Some brewing researchers of yore even went so far as to say that for Sparge water once Alkalinity is below 50 mg/L it is a moot point.

Yup, third sentence in, which is very strange that the pH won't come down/ OP has to keep adding acid.
 
I'm 72.
In Bru'n Water, v5.5, "sparge acidification" page, I change the "water volume to treat" to my mash + sparge water volume. Correct procedure Martin?
 
In Bru'n Water, v5.5, "sparge acidification" page, I change the "water volume to treat" to my mash + sparge water volume.

Not really. The whole 'treat water to 5.5 pH' is not a good approach and it then muddles the rest of the treatment. If you're starting with RO water, its alkalinity should already be low enough that further acidification to serve as sparging water, is not necessary. Additionally, the acidification needs for the mashing water might be markedly different than the sparging water. So, pretreating RO water or any water to a pH of 5.5 is not going to be ideal. The only benefit of treating to 5.5, is that its probably better than not treating at all.

Since the acidification requirements for sparging and mashing water can be so different, I recommend that Bru'n Water users leave the 'Water volume to treat' at "1" and then move on to the Water Adjustment sheet where you can separately enter your sparging and mashing water volumes to enable proper treatment calculations for those differing waters.
 
Thanks to Silver, Vike, marc1, and Martin setting me back on track. I got off track, reading articles and watching videos. Now, to brewing!
 
I'm not intending here to toss a proverbial 'Monkey Wrench' into the works, but this might be a good place to interject that AJ deLange did fully believe (counter to most of the rest of us) that acidifying "ALL" brewing water (as opposed to specifically 'Sparge' water) to ballpark 5.4-5.5 pH is generally a very good idea whereby to achieve a more level mash water playing field in addition to sparge water benefit. His "sticky" in this very forum titled "The 0 Effective Alkalinity Method" attests to this as his firm belief. And it has over 8,000 hits.

He keenly included the key word "Effective" in the title, as he well knew (and knows) that acidification to 5.4-5.5 pH does not actually zero Alkalinity. But rather that at pH 5.4-5.5 it (I.E., Alkalinity) is for all practical purposes of effectively zero consequence. Albeit that for darker and thereby likely to be more acidic beers it may be of mash water consequence...
 
Larry, AJ certainly recognized that some treatment was better than no treatment. But he never stated that this simplistic approach was better than a targeted approach.
 
Thanks, I like the continuing discussion. But I asked in my opening post if there is a lag time. In measuring pH after adding acid to RO, could I be eventually adding too much acid by measuring pH during the lag time. Anyone else experience a lag time?
 
Thanks, I like the continuing discussion. But I asked in my opening post if there is a lag time. In measuring pH after adding acid to RO, could I be eventually adding too much acid by measuring pH during the lag time. Anyone else experience a lag time?

As Silver mentioned above, measuring the pH of pure water is difficult. A quick internet search will generate lots of results like this:
https://www.vernier.com/til/1286
So it doesn't seem practical or necessary to measure or adjust the pH of RO or distilled water for brewing.

Have you tested the RO water with a TDS meter to see how good it is?
 
I have very alkaline tapwater, that otherwise tastes good. Most homebrewers here won't use it and buy RO water. I use the tapwater for the challenge, and because I'm lazy and hauling 6 gallons of water is hard. :) I have settled on adding 1ml of 85% phosphoric acid to each gallon of water, and that's usually all I do. The mash pH should be about 5.4 to 5.5 that way depending on the grist, but whatever it is (I don't measure it) I get good conversion and that's the main thing I care about. I've tried using lactic acid, and that works but I have to add too much to light-colored beers and it affects the taste. Lactic acid works just fine for dark beers because they need a little less, and the taste is more robust anyway. But using phosphoric for everything seems to work well.

If I brewed more often, I would learn to use Sauergut to acidify the mash, and sparge with warm water instead of hot so it doesn't extract tannins. I have played with that a little and I liked the results.
 
marc1, the RO is from a big chain grocery store machine, $0.39/gal. my refill containers. Testing the TDS of each gallon with an inexpensive pen meter, I get between 20 and 30, over the last several years. Once I got four 1 gallon jugs, and TDS varied between 50 and 75.
 
Try one of your local water softener system installers that also bottles and sells RO. The bottled RO I get from my local 'Clearwater Systems', which I fill myself at their facility, routinely tests at a metered 2 to 7 ppm TDS. I've tested gallon jugs of distilled water purchased from supermarkets that routinely come in higher in ppm TDS than Clearwater RO.
 
marc1, the RO is from a big chain grocery store machine, $0.39/gal. my refill containers. Testing the TDS of each gallon with an inexpensive pen meter, I get between 20 and 30, over the last several years. Once I got four 1 gallon jugs, and TDS varied between 50 and 75.

20-30 is OK, but 50-75 is a bit high - the machine probably needed to be serviced. It was still probably fine, though.

I've had one batch of beer that came out a little odd flavor-wise, and the star san I made from the RO water I got from a machine that day turned cloudy shortly after the brew session finished. After that I got a cheap TDS meter to check :D
 
marc1, I am wondering if Strong's recipe(s) are intended to mean a 5.5 pH in the mash, and to 5.5 in the sparge. That would be more in line with Martin's approach.

Martin, thanks for your opinion and in reply #15. I agree, but I neglected to explain after the pre-treatment of all the brewing water, I enter it in Bru'n Water as a 5.5pH source water, and determine acid requirements for the grain bill for the mash.

I read AJ's article "The 0 Effective Alkalinity Method." I like this paragraph quoted below:

"There isn't much that can be done about the fourth problem but the first three can be eliminated completely by simply adding enough acid to the brewing water to bring it to pHz. Water source secular variations, lab errors and calculator approximations are no longer a factor and we can leave the calculator to do what we really don't have much of an alternative for and that is to estimate the acid required by the malts. To do this we simply tell the calculator that the water's alkalinity is 0. It then calculates 0 for Items 1) and 2). On brew day one simply brings the water to pHz and then adds the additional acid demanded by the program with 0 alkalinity input."

Silver and marc1, your comments that determining pH of pure water is difficult due to low ion content validates my observation of variability in measuring pH of my RO.

As I posted before, I got off track. I am going to continue pre-treating the brewing water, but may go back to Martin's preference in his replys #15 and #18.
Thanks all.
 
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Larry, AJ certainly recognized that some treatment was better than no treatment. But he never stated that this simplistic approach was better than a targeted approach.

Anticipating such as this in advance is why I cautiously inserted "(counter to most of the rest of us)" into my interjection which introduced AJ's method. See post #17.

In fairness to AJ, he was trying to remove one variable (with that being the variable of Alkalinity), and generally when one (or ones software) has less variables to juggle it tends to increase predictive accuracy. Plus significantly back when AJ came up with 'Zero Effective Alkalinity' there were still popular mash pH assistant softwares and nomographs (and even various of rule of thumb empirical math models) 'and' (with all of these being clearly defined as "targeted approaches") attempting to resolve Alkalinity related complexities via the utilization of "Residual Alkalinity" (RA) based math models which are now well known to not work properly within the mash, at least in part due to observations pioneered by AJ, and then definitively nailed to the cross by Barth and Zaman, indicating gross errors (made by others, including software developers, and not Kolbach himself) in presuming that Kolbach's seminal work in establishing RA was relevant and applicable to mash step pH math modeling, when it never was (and still is) not.
 
I agree, but I neglected to explain after the pre-treatment of all the brewing water, I enter it in Bru'n Water as a 5.5pH source water, and determine acid requirements for the grain bill for the mash.

I'm not a Bru'nWater user, but I would bet that changing the pH for the source water doesn't change your predicted mash pH result, unless you're also changing a resulting bicarbonate number. And, starting with distilled water, bicarbonate would go from 0 to 0.

If you are starting with distilled/RO water and adding acid to bring the water's pH to 5.5, you're wasting your time. That tiny amount of acid (~ 0.025 ml 10% Phosphoric Acid or 0.002 ml 88% Lactic Acid per gallon) does nothing to move the needle on mash pH or buffer the sparge water. (And if you're adding more acid than that, something is wrong, because you'll overshoot the 5.5 you're aiming for.)
 
To make this simple (and as the OP now understands) both good Distilled and good RO water are 'Zero Effective Alkalinity' water(s).
 
When demineralized water comes into contact with carbon dioxide gas in the atmosphere, it quickly absorbs it, creating a dilute carbonic acid solution—making the pH of the water slightly acid.
 
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