How do I correlate "pHDI" with "Wort pH" for Weyermann malts?

[Silver_Is_Money]

I've seen a gaggle of Weyermann analytical data which indicates that their Pilsner malt lots tend to quite often cluster around 5.83 to 5.84 pH, which Weyermann is referring to as specifically this malt classes "Wort pH".

Is there a simple means whereby to correlate Wort pH to DI pH, as in transposing a malts Wort pH into a decent representation of its DI pH?

Edit: The Weyermann provided example of mash pH progression with the addition of increasing levels of their Acidulated Malt shows a DI pH that is initially 0.12 points below Wort pH, before any acidulated malt is introduced. Can this 0.12 difference be considered to be generally typical?

Edit #2: It is interesting that in this Weyermann example the Wort pH to mash pH differential increases to effectively double the initial differential as mash pH is reduced by the acidulated malt.

 

[Silver_Is_Money]

Or is it simply that in the Weyermann example there was likely a measure of alkalinity in the initial mash water, and for mashes done in RO or distilled water the DI_pH and the Wort pH would end up being one and the same?

I started thinking the two terminologies may be different measures of pH after A.J. started using 5.6227 as the DI_pH for his Weyermann Pilsner in a number of demonstrations of his various recent spreadsheets, and after seeing actual Wyermann data that indicates a typical 5.83-5.84 'Wort pH". Then the Weyermann acidulated malt example which charts both mash pH and Wort pH came along, with both of its sets of values being different, and seeming to confirm that the two are somehow rather demonstrably different.

 

[ajdelange]

In the terminology bandied about here pHDI refers to the pH of malt minimash made with about 40 grams of malt and 100 mL of DI water at about 50 °C which is supposed to be at least fairly closely related to what happens in a typical mash. The "Wort pH" specified by a maltster probably means the pH of the wort prepared in a Congress Mash carried out as follows:

Mash in 50 grams malt sample with 200 mL DI water to achieve a strike temperature of 45 °C (113 °F) and hold for 30 minutes. Then raise temperature 1 °C/min until 70 °C (158 °F) is reached. Add 100 ML DI water at 70 - 71 °C and hold at 70 °C for 1 hour. At the end of the hour the mash is cooled and made up to 450 grams, filtered and the extract of the filtrate determined and other tests made. Thus there is quite a difference in the procedure. In particular the rests and programmed rise intended to simulate, at least approximately, an entrie mash program whereas pHDI is supposed to reflect pH as soon after strike as the pH is relatively stable.

 

[Silver_Is_Money]

The average of the Weyermann data's difference between Wort pH and DI pH for the 12 data points of the acidulated malt example is 0.19, so it seems safe to conclude that the typical DI_pH (or pHDI) may be found to be about 0.2 points lower than that of reported Wort pH (or Congress mash) figures.

This fits A.J.'s 5.6227 to a tee.

A.J's 5.6227 + 0.2 is a respectable match to Weyermann's 5.83 to 5.84.

But more research is in order here, as the A.J. match to the Weyermann data may simply be a random coincidence.

 

[Big Monk]

The average of the Weyermann data's difference between Wort pH and DI pH for the 12 data points of the acidulated malt example is 0.19, so it seems safe to conclude that the typical DI_pH (or pHDI) may be found to be about 0.2 points lower than that of reported Wort pH (or Congress mash) figures.

This fits A.J.'s 5.6227 to a tee.

A.J's 5.6227 + 0.2 is a respectable match to Weyermann's 5.83 to 5.84.

But more research is in order here, as the A.J. match to the Weyermann data may simply be a random coincidence.

Weyermann's "Wort pH" IS the pH DI for the malt.

 

[Silver_Is_Money]

Weyermann's "Wort pH" IS the pH DI for the malt.

Thanks! I had suspected that may be the case. And that's actually perfect, as that is the premise I used for my mash pH software, which spans from 5.53 to 5.83 DI_pH via its 6 base malt 'drop down' selections.

Some lots of Rahr and Briess 2-Row Brewers type malts are rather acidic and at the lowest end, and some are a notch above it, while some lots of Pilsner are at the very highest end, and some are a notch below it, and for some cases Pilsner may hit above 5.85, while lastly the various of "pale" or "pale ale" classified malts fill in the 2 remaining of my 6 selector choices.

Briess data indicates that their Brewers malt clusters at about 5.53 to 5.58 (at least for the lots that represent my in hand data, with a single low outlier at 5.48), and their Pilsner hits 5.83. And their pales fall in-between.

 

[Silver_Is_Money]

I'm beginning to have a new outlook on mash pH. Since pH is observed (measured) to rise by about 0.22 points during the mash, my new opinion is that Weyermann's "Wort pH" terminology represents the pH when measured at the full completion and terminus of the mash cycle, and Weyermann's "Mash pH" represents the pH when measured at some juncture much earlier in the mash cycle. It is the "some juncture" (as in time) part that is presently an unknown. It may or may not be 20 minutes into the mash. But if you presumtively look at it this way, per Weyermann's own data ~5.38 pH at somewhere around 20 minutes into the mash will turn into ~5.60 pH at the terminus of the mash. But pH as measured before reactions are complete is a moving and variable target that can't truly be pinned down, whereas pH when measured at mash termination has reached a stable or static value. So putting it all together, the most consistent means by which to quantify "mash pH" success for a software set target of 5.4 pH is to achieve a measured end of mash pH of between roughly 5.60 to 5.64.

Final assessment:
1) The most proper (stable) time to measure pH is just prior to mash out, or at the completion of the mash step. Weyermann (per my conjecture) calls this "wort pH".
2) In the end "mash pH" as a term is uncertain (and thereby highly arbitrary) at ~20 minutes (give or take) due to its being at this juncture clearly a moving target, with this due to different recipes or grists (and mash temperatures and diastatic power factors, and mash water mineralization and acidification levels) mashing at different and overall highly variable rates (spanning from ~30 minutes to ~90 minutes or more, such that most mash for 60 minutes to sort of split the difference). I.E., "Mash pH" is essentially a figment of the imagination which only remains necessary due to current softwares requirement of its input.
4) Any terminus of the mash measured pH falling within the range of ~5.50 to ~5.80 should likely make you happy, and let you sleep good at night.
5) For maximum satisfaction in boasting with respect to software bragging rights, and for the specific case of a targeted "mash pH" of 5.4, one must definitively measure ~5.6 to ~5.64 "wort pH". For any other targeted mash pH, the formula: "wort pH = (targeted mash pH) +0.20 to +0.24 pH points" should be utilized to assess any mash pH assistant softwares phantom "mash pH" bragging rights.
6) Future software should target "wort pH" and abandon the targeting of "mash pH".
7) This does not change the presumption that any given malts DI_pH is also its "wort pH". What it does mean however is that if you intend to reliably measure your malts DI_pH you must do it no sooner than 60 minutes into the mashing of the malt test sample, and perhaps even at the 90 minute mark.

 

[Silver_Is_Money]

The Weyermann "mash pH/wort pH" stuff can be seen in the Sauermalz (acid malt) progression table presented within this pdf of what I believe was originally a Weyermann ppt presentation:
http://lowoxygenbrewing.com/wp-content/uploads/2016/11/Weyermann_TKW_Mash-pH_2010.pdf

 

[ajdelange]

I'm beginning to have a new outlook on mash pH. Since pH is observed (measured) to rise by about 0.22 points during the mash,

By whom? My mash pH's don't rise nearly that much. Do yours?

...my new opinion is that Weyermann's "Wort pH" terminology represents the pH when measured at the full completion and terminus of the mash cycle,

I really don't know what it means as the ppt presentation you reference gives no clue. I would assume, therefore, that it means a Congress Mash.

and Weyermann's "Mash pH" represents the pH when measured at some juncture much earlier in the mash cycle. It is the "some juncture" (as in time) part that is presently an unknown. It may or may not be 20 minutes into the mash.

Per their 5th slide mash pH is always to be meaured at the beginning of sacharification.

But if you presumtively look at it this way, per Weyermann's own data ~5.38 pH at somewhere around 20 minutes into the mash will turn into ~5.60 pH at the terminus of the mash.

Here's the congress mash procedure: Mash in 50 grams malt sample with 200 mL DI water to achieve a strike temperature of 45 °C (113 °F) and hold for 30 minutes. Then raise temperature 1 °C/min until 70 °C (158 °F) is reached. Add 100 ML DI water at 70 - 71 °C and hold at 70 °C for 1 hour. At the end of the hour the mash is cooled and made up to 450 grams, filtered and the extract of the filtrate determined. This is what is reported as the fine grind or coarse grind extract depending on which grinding protocol was carried out on the sample. Presumably "wort pH" would be measured at this time. And given Weyermanns prescription for when mash pH is to be measured that would be about 45 minutes in.

But pH as measured before reactions are complete is a moving and variable target that can't truly be pinned down, whereas pH when measured at mash termination has reached a stable or static value.

Mash pH is reasonably well pinned down 20 - 30 minutes after strike. It will change by at most a couple of hundredths beyond that point and it may go up or down depending on the mashing program, the amount of calcium in the water etc.

So putting it all together, the most consistent means by which to quantify "mash pH" success for a software set target of 5.4 pH is to achieve a measured end of mash pH of between roughly 5.60 to 5.64.

The best way to insure success would be to have programs and take measurements that deal with pH going into the fermenter but they wouldn't be of much use, would they? It has been long observed that if the strike pH is in the proper range, as measured at room temperature even, the pH at other points will more or less fall into place but more important it's a guarantee of a tasty beer (unless you screw up somewhere further along in the process).

Final assessment:
1) The most proper (stable) time to measure pH is just prior to mash out, or at the completion of the mash step. Weyermann (per my conjecture) calls this "wort pH".

The most proper time (equally as stable as mashout) in terms of its ability to communicate something of value to the brewer is 20 - 30 minutes after dough in. This assumes that doughin is at, at least, the ß gulcan rest temperature.

2) In the end "mash pH" as a term is uncertain (and thereby highly arbitrary) at ~20 minutes (give or take) due to its being at this juncture clearly a moving target, with this due to different recipes or grists (and mash temperatures and diastatic power factors, and mash water mineralization and acidification levels) mashing at different and overall highly variable rates (spanning from ~30 minutes to ~90 minutes or more, such that most mash for 60 minutes to sort of split the difference). I.E., "Mash pH" is essentially a figment of the imagination which only remains necessary due to current softwares requirement of its input.

Mash pH is just that. The pH of the mash. When it is taken determines how valuable a piece of information it is. A good brewer tracks pH throughout the process. He has in his mind a roadmap with mileposts (pH posts) along the way. He knows where the pH should fall at each step. The most valuable pH measurements to him are the one made 20 - 30 minutes into the mash and about 8 hours into the fermentation as mash pH in the proper range on the first and a healthy pH drop relative to pitching on the second tells him he is going to get a good beer.

4) Any terminus of the mash measured pH falling within the range of ~5.50 to ~5.80 should likely make you happy, and let you sleep good at night.

I would be very unhappy if I got an end of mash pH above 5.6.

5) For maximum satisfaction in boasting with respect to software bragging rights, and for the specific case of a targeted "mash pH" of 5.4, one must definitively measure ~5.6 to ~5.64 "wort pH". For any other targeted mash pH, the formula: "wort pH = (targeted mash pH) +0.20 to +0.24 pH points" should be utilized to assess any mash pH assistant softwares phantom "mash pH" bragging rights.

Bragging rights come when a program that purports to determine mash pH accurately determines mash pH. As we don't particularly care about wort pH except as an indicator that something is wrong because we know that proper mash pH is going to give us proper pH into the fermenter, a program that accurately predicts mash pH is the tool we need.

6) Future software should target "wort pH" and abandon the targeting of "mash pH".

Such software would be useless except as an academic tool to see if we can predict wort pH from malt data.

7) This does not change the presumption that any given malts DI_pH is also its "wort pH". What it does mean however is that if you intend to reliably measure your malts DI_pH you must do it no sooner than 60 minutes into the mashing of the malt test sample, and perhaps even at the 90 minute mark.

Measurement on malts show that there pH only changes by hundreths beyond 25 - 30 minutes.

Finally, I'd take that Wermann presentation and throw it in the trash. Errors are rife. Acidification of mash was tradionally done by malo-lactic fermentation? Where did the malic acid come from (malus = apple; malic acid is prevalent in fruits, not grains though grains doubtless contain some)? Malic acid is more acidic than lactic acid so how would conversion from it to lactic acidify anything? Malo-lactic fermentation is used in the wine industry to soften wines (lactic acid is mellower). Proper mash pH for lagers is 4.2 - 4.8 and for Berliner Weiße is 3.2 - 3.4? Those are the pH's of the finished beers. Acidifying wort increases phosphate buffering (it decreases it)? Wort pH is 0.13 - 0.24 higher that mash pH with the more sauermalz in the grist the higher the rise? That doesn't make much sense either.

 

[Silver_Is_Money]

By whom? My mash pH's don't rise nearly that much. Do yours?

1) Two independent verifications of this within just this month here on the forum. Plus***

2) Until recently I've always presumed that if I pull a sample at 15-20 minutes into the mash, that is the mash pH, so I've never measured twice.

*** I seem to also recall where Martin Bruingard has stated (more than once) that from his observation mash pH rises over time. Or perhaps what he was saying was that he has watched it both rise and fall over time, wherein if above target it will fall, and if below target it will rise. Perhaps he will jump in and lend clarification to my presumption of his position, as it is not my place to presume his intent.

 

[Silver_Is_Money]

I would be very unhappy if I got an end of mash pH above 5.6.

Weyermann states that "wort pH 5.79" = "mash pH 5.62". So perhaps I shouldn't have allowed for an upper limit of 5.80, and I should have cut "wort pH" off at an upper limit of 5.75 (which per Weyermann equates to a mash pH of 5.56).

 

[Silver_Is_Money]

One forum member tracked a rise from an initial pH 5.42 at ~15 min. to a final pH of 5.61 - 5.63, and another watched an initial pH of 5.57 at the 23 minute mark wind up being 5.71 at the 90 minute mark of the mash.

 

[mabrungard]

I seem to also recall where Martin Bruingard has stated (more than once) that from his observation mash pH rises over time. Or perhaps what he was saying was that he has watched it both rise and fall over time, wherein if above target it will fall, and if below target it will rise. Perhaps he will jump in and lend clarification to my presumption of his position, as it is not my place to presume his intent.

Yes, that is a phenomena I've repeatedly observed. My observations are that wort pH tends to trend toward around 5.4 with time.

 

[Silver_Is_Money]

Yes, that is a phenomena I've repeatedly observed. My observations are that wort pH tends to trend toward around 5.4 with time.

Thanks Martin!

 

[ajdelange]

Martin thinks mash naturally buffers at 5.4. I doesn't and I've explained that to him perhaps half a dozen times but another round may lend some insight into the broader subject at hand. Let's start with the observation that Martin knows how to measure pH. He's had plenty of experience and practice at it. Notice that he isn't reporting migration of mash pH's to 5.7 and 5.8. He's reporting migrations to 5.4. The reason he is seeing 5.4 all the time is because he is measuring mashes for which that is the near equilibrium pH. He doesn't (I don't think) formulate grists in the hope of achieving pH 5.8 but he can tell us if he does. The mechanism responsible for the early rapid change I have stated here dozens of times. When acids or bases are dissolved in the liquor what one measures early on, that is, before the liquor has had a chance to penetrate and react with the grist, is the pH of the acidified or alkalinized liquor. Adding a few mL of lactic acid to a couple of gallons of low alkalinity water drops it's pH way down below the desired mashing range. Over time the system moves towards equilibrium. And yes we know it's not really equilibrium. It will continue to drift a tiny bit for a long time. But the amount of drift isn't tenths of pH per hour. It's hundredths. What happens in the second hour to change that to tenths?

Now I should know better than to say or imply "never" in brewing. All I can say is that in dozens of mashes making beer and in hundreds of test mashes I have never seen a drift beyond 30 minutes that would suggest wort pH rise as much as in that Weyermann presentation. I would want to question Herr Weyermann as to how he obtained those values. I've just found out that Murphy's doesn't know the difference between ATC correctable pH drift and pK drift induced pH shift and White Labs doesn't either. Can we trust Weyermann? A few questions would answer that but given all the other errors in that presentation I can't take it very seriously. How about the reported incidents here? As I noted above I would trust Martin's measurements but I wouldn't trust the guy who recently posted that he calibrates his meter every month whether it needs it or not. You say you have never measured pH down stream of the mash. Perhaps you should. How do you know you are coming out of the kettle with pH below 5.4? I will once more state that I'm not saying it can't happen but I will also restate that I've never seen it and common sense seems to dictate against it.

I really think that you are leading yourself deeper into the forest in assuming that wort pH is going to rise relative to mash pH. When I used to brew with more calcium it would be lower with a small drop after each decoction. Now that I am using minimal calcium I find it a bit higher so there is, at least, one brewer's observation that at least under some circumstances wort pH stays about the same or even drops slightly.

 

[ajdelange]

Weyermann states that "wort pH 5.79" = "mash pH 5.62".

Where do they say that?

 

[Silver_Is_Money]

Where do they say that?

Same line on the Saurmalz acidification data page.

 

[ajdelange]

Thanks. That's what I thought. As I've said a couple of times earlier I wouldn't rely on that presentation as the basis for global conclusions.

 

[Silver_Is_Money]

Thanks. That's what I thought. As I've said a couple of times earlier I wouldn't rely on that presentation as the basis for global conclusions.

I agree that the Weyermann presentation is highly flawed. I hope that at least it is not flawed in its assessment that a lot of Sauermalz which is representative of their acid saturation norm will move the grist pH downward 0.1 pH points for each 1% added to the grist.

 

[ajdelange]

That is more or less true but as they say the drop depends on many factors. Obviously the buffering of the rest of the grist is one of them. It's a rule of thumb. Treat it as such.

 

[Silver_Is_Money]

It has taken some time, but I have finally come across a 2004 dated peer reviewed paper which clearly differentiates between "mash pH" and "wort pH". The study acidified all mashes to a measured pH 5.4 via various biological and chemical means and also took what were specifically called "wort pH" samples at the end of mashing and post lautering (which means pre-boil).

Mash pH's were all adjusted to pH 5.4 as measured at 50 degrees C. (122 degrees F.) at the beginning of step mashing (and after a hold at 50 degrees C. for 30 minutes).

Wort pH's were subsequently measured for each batch at between 5.8 to 5.9 (call it 5.85 as an average) and all "wort pH's" were measured at 20 degrees C. at the end of mashing and post lautering.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.2004.tb00192.x

I find it interesting that this study actually took and pH adjusted its mash pH samples at mash temperature, albeit that mash temperature was 50 degrees C. (122 degrees F.). This is the first evidence I've come across whereby mash pH is confirmed to have been intentionally measured at mash temperature.

 

[Silver_Is_Money]

If we apply an approximation* of 0.004 pH points of measured pH shift per degree F. of measurement temperature differential to the above, we see that for moving from 122 degrees F. to 68 degrees F. there should be an upward pH shift of (122-68)*0.004 = 0.216 points due to measurement temperature differential alone.

Since all samples in the above referenced link to the peer reviewed study were adjusted to a mash pH of 5.4 at 122 degrees F., if we apply the upward shift of 0.216 pH points, they were all effectively adjusted via acidification to 5.616 pH as measured at 68 degrees F. (after 30 minutes of mashing at 122 degrees F.).

That each sample subsequently measured (on average) 5.85 pH at the very end of the step mashing sequence and post mash-out plus lautering indicates that during the mash the wort rose an additional 5.85-5.616 = 0.234 points.

This observed upward shift of 0.234 points figure is well in agreement with the Weyermann supplied data chart which indicates a typical 0.22 pH point rise between what they specifically refer to as "mash pH" and what they specifically refer to as "wort pH". Thus I believe that from this agreement we can now conclude that "mash pH" and "wort pH" are not the same thing.

* : 153 degrees F. minus 77 degrees F. = 76 degrees of differential. 76 x 0.004 = 0.30 points of expected pH shift if one measures pH at a typical 67 degree C. (153 degrees F.) mash temperature vs. the generally accepted pH measurement temperature of 25 degrees C. (77 degrees F.).

 

[Silver_Is_Money]

The EBC standardized method for the measurement of wort pH is defined by EBC rule 8.17. It calls for wort pH to be measured at 20 degrees C.

https://brewup.eu/ebc-analytica?page=9

There does not appear to be an EBC or ASBC standardized mash pH procedure method (which is perhaps an indicator of its industry relevance). However, my search for this industry standardized method continues.

 

[Silver_Is_Money]

The more I search peer reviewed papers, the more I'm discovering that those associated with the brewing industry are not very concerned (if they are concerned at all) with mash pH, and alternately that they appear to be highly concerned with wort pH.

 

[Silver_Is_Money]

Per the book titled "Brew like a Monk" it appears that Rochefort (at least, among the Trappists who tend to at least occasionally assist each other with methodology, yeast, recipes, etc...) intentionally mashes at a pH of 5.8 to 5.9, and then subsequently mineral acid acidifies the downstream wort. Their results seem to indicate that this method works exceedingly well.

 

[Silver_Is_Money]

I'm beginning to change my perspective as to whether the oft quoted mash pH range of 5.2 to 5.6 is intended to be measured at room temperature or mash temperature (as well as questioning the range of pH 5.2 to 5.6 itself as being the ideal).

Since temperatures and pH's are intricately linked with respect to enzymatic activity, I'm now starting to lean toward the brewers prime concern for pH being considered as it relates to mash temperature and enzymes (with pH, enzymes, and mash temperature being considered to be intricately linked together, rather than considered separately).

The best safe compromise (from the perspective of probe longevity as well as typical instrument calibration temperature) seems to be mashing at pH 5.6 as measured at room temperature, as this should yield a roughly 5.3 actual pH at mash temperature. 5.3 pH actual (which means the pH observed at mash temperature) just hits the lower end of the ideal pH range for Alpha Amylase enzyme and is nigh on midrange perfect for Beta Amylase enzyme.

I will therefore be targeting a room temperature (20 degrees C., 68 degrees F.) measured mash pH of 5.6 for awhile to see how this impacts my perspective upon flavor and mouthfeel. If you have the fortitude to attempt direct mash temperature pH measurement, you will be looking for 5.3 pH.

Since software presumes room temperature it should be set to a target of 5.6 pH. This will yield roughly 5.3 pH at mash temperature.

 

[Silver_Is_Money]

If you follow along with the above (and I'm not yet universally encouraging it) you will then likely need to also adjust post boil and cooling kettle pH via acidification, and for this the ideal target appears to be 5.1 to 5.2 pH as measured at 20 degrees C.

 

[Silver_Is_Money]

If pressed for an ideal room temperature measured range of mash pH acceptability, 5.4 to 5.8 would be the recommendation that most agrees with my current line of thinking, and (if pressed) a broader range of 5.3 to 5.9 would be nominally acceptable. This places the 5.8 to 5.9 Rochefort mash pH's within either window of acceptability (with due mention that they assuredly acidify post boil and cooling).

 

[Silver_Is_Money]

Here is an interesting find. An employee of Rahr states that in 2017 Rahr measured the "Wort pH" of 100 lots of what I must initially presume to be typical Rahr 2-Row, as measured at 20 degrees C. (68 degrees F.) in compliance with EBC rule # 8.17, and the (left unpublished) "wort pH" result was a mind boggling 5.98 pH.

If we back off ~0.23 pH points to arrive at a nominal "mash pH" we get ~5.75 (for the case of measurement at 20 degrees C.). And if we next back off an additional ~0.3 points to see what this mash pH might nominally have looked like if taken at actual mash temperature we arrive at ~5.45 pH.

https://byo.com/mr-wizard/setting-record-straight-mash-ph/

I'm now recommending that manufacturers reported Congress Mash "Wort pH" values be reduced by 0.22 to 0.24 pH points to arrive at a nominal 20 degrees C. measured "DI Mash pH" value.

 

[mabrungard]

If you follow along with the above (and I'm not yet universally encouraging it) you will then likely need to also adjust post boil and cooling kettle pH via acidification, and for this the ideal target appears to be 5.1 to 5.2 pH as measured at 20 degrees C.

I agree that there seems to be benefits in mashing and boiling at around 5.4 and acidifying to a lower pH following that.

 

[Silver_Is_Money]

On page 115 of the 2004 published and peer reviewed book titled "Brewing Science And Practice" (by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes, and Roger Stevens) is found the following statement:

Infusion mashes are best carried out at pH 5.2 - 5.4 (mash temperature), and so will give cooled worts with pH values of about 5.5 - 5.8.

This ought to about seal the case and nail it shut for mashing at 5.5 - 5.8 pH as measured at room temperature. The midrange here is 5.65 pH as measured for mash samples cooled to room temperature (which in the brewing industry means 68 degrees F. or 20 degrees C., per EBC rule 8.17). This documentation would indicate that ~5.65 should be the target pH at which mash pH assistant software is set so as to determine acidification or caustification requirements. We have nearly all apparently been collectively doing mash pH adjustment wrongly for years.

http://vinic.com/files/books/Brewing_Science_and_Practice__2004_.pdf

 

[mabrungard]

This ought to about seal the case and nail it shut for mashing at 5.5 - 5.8 pH as measured at room temperature.

Nope. That is just one source. There are other sources that do cite room-temperature pH measurement. Additionally, I invite any brewer to perform a pale beer mash in that pH range and see if the beer is better than when mashed closer to 5.4. I don't find that its true, in my experience.

The only caveat I can apply is effect of post-boil acidification. While that is a British text, I'm not sure that its common for British brewers to perform any sort of post-boil acidification like the continental Europeans might do.

 

[Silver_Is_Money]

Nope. That is just one source. There are other sources that do cite room-temperature pH measurement. Additionally, I invite any brewer to perform a pale beer mash in that pH range and see if the beer is better than when mashed closer to 5.4. I don't find that its true, in my experience.

I've been searching brewing industry level documents. I grant that many homebrewing oriented dissertations and books insist upon 5.2 to 5.6 mash pH at room temperature, but that is not what I'm focusing upon. That aside, the book I referenced above also gives its expectations as to room temperature mash pH, as can be seen within my quote.

In an admittedly highly limited way I've already tested this. The best infusion mashed Bohemian Pilsner I ever brewed occurred many years ago, and well before most of us were paying much attention (if any) to mash pH. When I run that old recipe through software today I find that it likely mashed at around 5.75 - 5.8 pH for measurement done at room temperature. And I've also referenced a book that indicates that a well renowned Trappist Ale brewery mashes intentionally at 5.8 to 5.9 pH.

 

[Silver_Is_Money]

The problem with available data on mash pH comes down to one of circular reasoning, as can be seen from this Charles W. Bamforth quote taken from his paper titled "pH in Brewing: An Overview":

There have been surprisingly few (if any) detailed studies of the precise impact of pH on mashing performance and wort composition. Textbooks of brewing make reference to “optimum” pH’s for parameters such as extract and “wort filtration”, though they are conspicuous by the lack of references. One textbook refers to a previous textbook! It seems that a largely empirical approach has been employed. How the data has been generated and on what scale (lab mashes are not always good mimics of commercial mashes) is unclear.

Circular reasoning based merely upon empirical guesswork is essentially what we see today. Repetition of what one unreferenced person guessed at some point in the obscure past is repeated until it mystically becomes truth. And this paper admits that this problem exists even at the commercial level, let alone at the homebrew level.

Per Wikipedia: Charles W. Bamforth is the Immediate Past President of the Institute of Brewing and Distilling and Anheuser-Busch Endowed Professor of Malting and Brewing Sciences at University of California, Davis.

 

[eric19312]

The more I search peer reviewed papers, the more I'm discovering that those associated with the brewing industry are not very concerned (if they are concerned at all) with mash pH, and alternately that they appear to be highly concerned with wort pH.

My quick reaction to this idea is that it makes a lot of sense as it would take out all the ambiguity in sampling time introduced by so many possible ways to conduct a mash.

 

[Silver_Is_Money]

My quick reaction to this idea is that it makes a lot of sense as it would take out all the ambiguity in sampling time introduced by so many possible ways to conduct a mash.

Exactly. It greatly demystifies the entire process.

 

[Vale71]

Here is an interesting find. An employee of Rahr states that in 2017 Rahr measured the "Wort pH" of 100 lots of what I must initially presume to be typical Rahr 2-Row, as measured at 20 degrees C. (68 degrees F.) in compliance with EBC rule # 8.17, and the (left unpublished) "wort pH" result was a mind boggling 5.98 pH.

If we back off ~0.23 pH points to arrive at a nominal "mash pH" we get ~5.75 (for the case of measurement at 20 degrees C.). And if we next back off an additional ~0.3 points to see what this mash pH might nominally have looked like if taken at actual mash temperature we arrive at ~5.45 pH.

https://byo.com/mr-wizard/setting-record-straight-mash-ph/

I'm now recommending that manufacturers reported Congress Mash "Wort pH" values be reduced by 0.22 to 0.24 pH points to arrive at a nominal 20 degrees C. measured "DI Mash pH" value.

There's nothing mind boggling about the reported average value. As a matter of fact, between 5.95 and 6.00 is the recommended range for light colored malt. Please bear in mind that this is measured on wort from a standardized Congress Mash wich has a mash thickness of 9:1 (very thin) and is performed with distilled water. Just going from 9:1 to 4:1 will drop the PH by approximately 0.35 which in the case of Rahr would give an average wort PH of 5.63.
I really don't follow your adjustments though and I don't see why Rahr should report a value different from what they have actually measured using the accepted standard methodology.

 

[Robert65]

Please bear in mind that this is measured of wort from a standardized Congress Mash wich has a mash thickness of 9:1 (very thin) and is performed with distilled water. Just going from 9:1 to 4:1 will drop the PH by approximately 0.35....

Thank you. Now I understand why, when I test a sample in distilled water, I get a much lower value than is given on the COA, more in line with the values given by Kai's paper, for example, than data sets I've seen applied in some software; and explains why using those higher values in my own calculations gives very inadequate predictions of real, measired mash pH. I test samples in distilled water, but using a normal grind and mash thickness. I had thought there might be something amiss in my measurement, instead it was something amiss in my understanding.

 

[Vale71]

Now that you mention it, the finer grind of a Congress Mash would also influence PH but in the opposite direction, i.e. lower than with a coarser grind, so in the end you will have two distinct differences acting on mash PH but in opposite directions making accurate predictions even more difficult.

 

[Robert65]

It also puts into perspective a tidbit in Kunze that's confused me. He says that Kolbach found that to reduce mash pH by 0.01 requires something like 60 mEq/kg of acid but to reduce wort requires 30. My experience suggests that the requirement for mash is nearer the 30 figure. If these studies by Kolbach were performed under specific laboratory conditions, our mashes may behave more like his wort.