pH: How important is adjusting for pH

[ajdelange]

I think I have a grasp of what sixhotdogneck is getting at. I believe the contentions are that a) the mash pH is somewhat flexible

That's not quite what he said. He said:

As long as conversion is complete, overly alkaline water was avoided and no mash hopping was present there should be no flavor profile difference in the wort produced from the mash.

If that's literally what he means I can't comment because I've usually only cursorily taste the wort because it tastes good. I have never tried to make any judgement as to whether worts mashed with pH control taste better than ones that were made without regard to it. It's the beer I care about and definite improvement is seen there. Whether he meant to say beer or wort "no flavor profile difference" implies to me that "somewhat flexible" is too weak a reading of his position.

At this point what I would hope he would do is tell us why he thinks this is the case and to resolve the conflict between the statements that mash pH doesn't matter and the statement that alkalinity should be avoided as the effect of alkalinity on mash is to raise it's pH. So far his responses to requests for elucidation only result in repeats of the assertion which is stated as absolute fact without any support - not even the "that's the way I do it and my beers are great" response which one so often sees in cases like this. Were he to offer some explanation we might then have the basis for some discussion of the sort that I believe to be the reason for the Brewing Sciences Formum - such as the info you have provided about enzymes. Speaking of enzymes I will again try to make people cognizant of the fact that maximizing extract is not the only concern here. Beer flavor is. There are a dozen or so "mashing enzymes" (list in Charlie B's paper - my thanks to cire too for posting that) but are there not thousands of others that are involved in the myriad other metabolic pathways that produce beer flavors (what I am concerned with here). Also consider the following reaction which should be familiar: CH3CHO + NADH + H+ <--> CH3CH2OH + NAD+. Obviously it doesn't take place in the mash and I use it because it is familiar and I can't site any specific similar reaction which does take place in the mash but isn't it reasonable to assume that there must be some similar (redox) reactions going on? The point here being that this is an enzyme catalyzed reaction. Supposing the enzyme's activity to be completely flat from DC to daylight the reaction is still clearly pH dependent (especially interested in hopjuices comment on this). Bamforth also notes other pH dependent effects such as solubiliztion of polarized mash components. Hotdog has also stated that phenol solubility is not a function of pH. I wish he'd give us his reasoning on that too.

While on the subject of the Bamforth paper (which I haven't seen in years) Equation 10 is wrong. The buffering capacity is (Added H+ or OH-)/(Change in pH). Also I believe the summary says it very well. The matrix is too large. I presented at a 3 day (large matrix there too) conference at the Catholic University of Louvaine entitled "The pH Paradox" with the paradox being that there is no answer as to what the proper pH should be. There was no question, however, that it needed to be controlled throughout the brewing process.

That start of boil pH is what helps controls protein coagulation and precipitation, hop utilization (taste) and yeast control

No question about the first two but it's pretty well known that wort pH has but a small effect on fermentation pH. I stated many times, however, that if you present yeast with a basic medium they will have to work at acidfying it which is not what we hired them to do.

all which have a much more prevalent effect on the final product.

Another problem statement in that it is put forth without any support whatsoever. Why should this be? How can this be? It denies that pH can have any effect on mash and given that pH is so important in other biological systems (if our blood pH gets outside approximately 7.3-7.5 we are in trouble). Why is a mash different?

I have found lots on the profound impact the pH of the final beer has on flavor, flavor stability, and other physical properties of the beer. These studies were done by either adulterating the pH of the kettle or the pH of the final beer. Lots on pH, temp, sparging and final beer qualities (less convincing, to be honest). Several on the pH of the mash and conversion efficiency, some of which date back to the 60s and report quite efficient mashes at “unusual” pHs, but no sensory evaluation of the final beers. I actually couldn’t find anything directly relating mash pH to final beer properties. Please, please correct me if you know of peer reviewed publications that have this kind of data!

No I don't. As Charlie says given the importance attached to pH in brewing, why haven't such studies been done?

As it stands, this gap is glaring to me. Where is this data? Is it because it is actually the kettle pH and not the mash pH that really matters? Or even just the final beer pH that really matters (someone pointed out the amazing pH correcting abilities of yeast)? Perhaps the importance of the mash pH is really more about setting the kettle pH than a magical effect in the mash itself?

Brewers know that if you get the mash pH right the pH will tend to track throughout the rest of the process though some make additional pH corrections in the kettle and some in the finished beer itself. The idea of ignoring mash pH and just setting kettle pH is entirely foreign to me. I have never heard of anyone doing it and can't imagine why anyone would.

Though sixhotdogneck hasn’t backed up his/her claims with any real data, I’m starting to think that maybe, just maybe there is something to it. Someone please disabuse me of this notion with something other than anecdotal evidence and I will be in your debt.

Well maybe there is but he has no credibility in my mind at this point not totally because his idea conflicts with the accepted science and brewery practice but also because of his other absurd (in terms of accepted science) comments about phenol stability.

I realize I may be questioning decades of brewing science but as an academic scientist I am trained to say “someone told you what? Where did they get that? Show me the peer-reviewed literature to back it up and then we’ll discuss it.” So, I apologize in advance for my skepticism, I’m legitimately trying to learn (even after >25 years of brewing….).

100% behind these sentiments. I don't think we're going to get any peer reviewed literature here. At this point I'll even welcome some anecdotal data or even some reasoned surmise based on the science.

 

[sixhotdogneck]

That's not quite what he said. He said:

If that's literally what he means I can't comment because I've usually only cursorily taste the wort because it tastes good. I have never tried to make any judgement as to whether worts mashed with pH control taste better than ones that were made without regard to it. It's the beer I care about and definite improvement is seen there. Whether he meant to say beer or wort "no flavor profile difference" implies to me that "somewhat flexible" is too weak a reading of his position.

At this point what I would hope he would do is tell us why he thinks this is the case and to resolve the conflict between the statements that mash pH doesn't matter and the statement that alkalinity should be avoided as the effect of alkalinity on mash is to raise it's pH. So far his responses to requests for elucidation only result in repeats of the assertion which is stated as absolute fact without any support - not even the "that's the way I do it and my beers are great" response which one so often sees in cases like this. Were he to offer some explanation we might then have the basis for some discussion of the sort that I believe to be the reason for the Brewing Sciences Formum - such as the info you have provided about enzymes. Speaking of enzymes I will again try to make people cognizant of the fact that maximizing extract is not the only concern here. Beer flavor is. There are a dozen or so "mashing enzymes" (list in Charlie B's paper - my thanks to cire too for posting that) but are there not thousands of others that are involved in the myriad other metabolic pathways that produce beer flavors (what I am concerned with here). Also consider the following reaction which should be familiar: CH3CHO + NADH + H+ <--> CH3CH2OH + NAD+. Obviously it doesn't take place in the mash and I use it because it is familiar and I can't site any specific similar reaction which does take place in the mash but isn't it reasonable to assume that there must be some similar (redox) reactions going on? The point here being that this is an enzyme catalyzed reaction. Supposing the enzyme's activity to be completely flat from DC to daylight the reaction is still clearly pH dependent (especially interested in hopjuices comment on this). Bamforth also notes other pH dependent effects such as solubiliztion of polarized mash components. Hotdog has also stated that phenol solubility is not a function of pH. I wish he'd give us his reasoning on that too.

While on the subject of the Bamforth paper (which I haven't seen in years) Equation 10 is wrong. The buffering capacity is (Added H+ or OH-)/(Change in pH). Also I believe the summary says it very well. The matrix is too large. I presented at a 3 day (large matrix there too) conference at the Catholic University of Louvaine entitled "The pH Paradox" with the paradox being that there is no answer as to what the proper pH should be. There was no question, however, that it needed to be controlled throughout the brewing process.



No question about the first two but it's pretty well known that wort pH has but a small effect on fermentation pH. I stated many times, however, that if you present yeast with a basic medium they will have to work at acidfying it which is not what we hired them to do.


Another problem statement in that it is put forth without any support whatsoever. Why should this be? How can this be? It denies that pH can have any effect on mash and given that pH is so important in other biological systems (if our blood pH gets outside approximately 7.3-7.5 we are in trouble). Why is a mash different?



No I don't. As Charlie says given the importance attached to pH in brewing, why haven't such studies been done?


Brewers know that if you get the mash pH right the pH will tend to track throughout the rest of the process though some make additional pH corrections in the kettle and some in the finished beer itself. The idea of ignoring mash pH and just setting kettle pH is entirely foreign to me. I have never heard of anyone doing it and can't imagine why anyone would.

Well maybe there is but he has no credibility in my mind at this point not totally because his idea conflicts with the accepted science and brewery practice but also because of his other absurd (in terms of accepted science) comments about phenol stability.



100% behind these sentiments. I don't think we're going to get any peer reviewed literature here. At this point I'll even welcome some anecdotal data or even some reasoned surmise based on the science.

You seem like a really angry individual. I hope that's not the case and that I'm misinterpreting your posts.

I'm simply presenting an idea that @hopjuice_71 interpreted and summarized very well.

Instead of constant negativity let's define an experiment that will prove/disprove the validity.

1.) Make 5gal of wort of several different styles by mashing for 60 mins - an appropriate grist with distilled water - standardize water salts for each.
a.) Pilsner or pale (half teaspoon of CaCl)
b.) Brown (half teaspoon of CaCl, half teaspoon of CaSO4)
c.) Stout (half teaspoon of NaCl)
2.) For each mash record the taste of the wort @ 10 min intervals
3.) For each mash record the pH of the wort @ 10 min intervals
4.) At 60 mins stop mashing and adjust the boil start pH of each to 5.1 using phosphoric acid/maybe sauergut.
5.) Continue with the boil and normal hopping as per recipe.
6.) Ferment each with a standard yeast US05 perhaps
7.) (repeat the above using a mash pH calculator adjusting mash pH with phosphoric or baking soda but not boil start pH) After 6 weeks do triangle tests on each style

 

[ScrewyBrewer]

@sixhotdogneck that would be an ambitious undertaking to say the least.

 

[Silver_Is_Money]

Here's one that might rock your socks. An employee of Rahr states that data taken from their internal (and unpublished) lab test results on 100 lots of Rahr 2-Row indicate an average "wort pH" of 5.96. There's that "wort pH" terminology thing, along with it being sky high again. My rule of thumb has been to subtract 0.2 pH points from "wort pH" to arrive at "DI_pH". But who knows if this rule of thumb is correct, or what "wort pH" even is for that matter. Some say it is the same thing as DI_pH. At that, even 5.76 DI_pH for standard Rahr 2-Row seems high when some people insist it is more in line with about 5.55.

The average wort pH (measured at 20˚C/68 °F) from 100 samples taken from 100 different batches of malt from production lots of North-American, pale, 2-row malted barley was pH 5.98 (data not published and taken from internal lab results from 2017).

Lots of mash pH info in the article also:

The article also says the best pH range for room temperature pH monitored mashing spans from 5.55 to 5.85, which means a midrange of 5.7 pH.

The rule-of-thumb pH range of 5.2-5.5 is the pH of the actual hot mash, not the cooled sample. This means that the temperature-corrected pH is about 0.35 units higher, or pH 5.55-5.85.

Here's the link to the published article:
https://byo.com/mr-wizard/setting-record-straight-mash-ph/

 

[J-T]

Discussed this article a while back in another forum thread.
https://www.homebrewersassociation.org/forum/index.php?topic=31200.0

Here's one that might rock your socks. An employee of Rahr states that data taken from their internal (and unpublished) lab test results on 100 lots of Rahr 2-Row indicate an average "wort pH" of 5.96. There's that "wort pH" terminology thing, along with it being sky high again. My rule of thumb has been to subtract 0.2 pH points from "wort pH" to arrive at "DI_pH". But who knows if this rule of thumb is correct, or what "wort pH" even is for that matter. Some say it is the same thing as DI_pH. At that, even 5.76 DI_pH for standard Rahr 2-Row seems high when some people insist it is more in line with about 5.55.



Lots of mash pH info in the article also:

The article also says the best pH range for room temperature pH monitored mashing spans from 5.55 to 5.85, which means a midrange of 5.7 pH.



Here's the link to the published article:
https://byo.com/mr-wizard/setting-record-straight-mash-ph/

 

[corax]

I used to live where I apparently had great water. I never got into water or pH adjustments, 1) because my beers were good. 2) because I didn't get around to sending off a sample or buying a meter.

I am questioning how soon I will get into really checking water and pH since I don't think the water where I am now is nearly as versatile as it was. I have always thought I would make the step into water treatment, but it seems more important now.

I'm strongly of the opinion that homebrewers worry way too much about, and fuss way too much with water treatment. Untreated soft water makes great beer, regardless of style. And if you don't have soft water, you get the same results with MINIMALLY TREATED RO water.

(NOTE: I'm even more strongly of the opinion that you should do whatever you enjoy when pursuing a hobby, so if fussing too much with water treatment is what you enjoy, CARRY ON!)

I am a big advocate of using pH strips instead of pH meters. For mashing, I use the pH 4 to 7 strips. Here's why:

1. pH strips are accurate enough. +/- 0.1 pH unit simply does not make a significant difference.
2. The accuracy and precision of pH strips are in line with each other. The precision of pH meters far outstrips their accuracy. I see people here reporting pH to two significant digits, and depending on my mood I either roll my eyes or laugh out loud.
3. pH strips are cheap.
4. pH strips are foolproof. I'm confident that AJ DeLange and a couple others here can properly calibrate and use a pH meter. But yer average homebrewer? Not so much.

How important is it? I think it's important to be in the right range, but if you've got reliable water and you're in range every time you check, then you will probably be OK if you "forget" a time or two.

 

[mabrungard]

1. pH strips are accurate enough. +/- 0.1 pH unit simply does not make a significant difference.
2. The accuracy and precision of pH strips are in line with each other. The precision of pH meters far outstrips their accuracy. I see people here reporting pH to two significant digits, and depending on my mood I either roll my eyes or laugh out loud.
3. pH strips are cheap.
4. pH strips are foolproof. I'm confident that AJ DeLange and a couple others here can properly calibrate and use a pH meter. But yer average homebrewer? Not so much.

I wish your conjecture was true.

1. If you could actually read pH strips accurately due to the effect of colored wort, your first half of your first point would hold more water. However, I do agree that slicing the baloney any finer than a tenth of a standard pH unit is useless in brewing.

2. While having the ability to read pH to the hundreths is again useless in the big picture of brewing, it is useful for establishing when a reading is stable. Otherwise readings to a tenth are fine. But there is NO WAY that anyone can guesstimate what a pH strip is reading when you're dipping it in colored wort. In addition, pH strips require somewhat 'strong' ionic solutions for them to report pH very accurately. While we might think that wort is 'strong', its not very strong in the ionic sense.

3. I'll concede that point to a degree. The 'good' pH strips (plastic, not paper) are not all that cheap. The paper strips are truly useless for brewing.

4. pH strips certainly subject to being fooled. Colored wort alters their reporting and the ionic strength issue can still rear its head.

pH strips are not the panacea that you think they are.

 

[ajdelange]

You seem like a really angry individual. I hope that's not the case and that I'm misinterpreting your posts.

Angry? Why would you conclude that? I am actually quite amused at the variety of ways in which you dodge the basic question "Why do you think these things?"

I'm simply presenting an idea that @hopjuice_71 interpreted and summarized very well.

This may speak volumes. Does it say that this is an idea that just popped into your head that seems like a good idea to you, or at least a hypothesis worth testing, but for which you have no basis in your own experience, that of others or the literature? It may indeed be a hypothesis worth testing but one doesn't offer up a hypothesis as fact until it has been tested.

Instead of constant negativity let's define an experiment that will prove/disprove the validity.

Not sure where the negativity has come in but before we can test a hypothesis we have to define it and that's a little tricky here because of the way you have posted it. The best I can come up with is:

H1: The quality of a fermented beer whose wort pH has been adjusted is not dependent on mash pH unless mash pH has been influenced by alkalinity.
H0: The quality of a fermented beer whose wort pH has been adjusted is dependent on mash pH

As long as conversion is complete, overly alkaline water was avoided and no mash hopping was present there should be no flavor profile difference in the wort produced from the mash.

This statement leaves some questions as to what your hypothesis is. Does "overly alkakine" imply that H1 should be worded H1: The quality of a fermented beer whose wort pH has been adjusted is not dependent on mash pH unless mash pH has been influenced by overly alkaline water?. Should it be changed to H1: The quality of a fermented beer whose wort pH has been adjusted is not dependent on mash pH as long as the alkalinity of the liquor is < x mEq/L. If so, what is x? Am I totally wrong in mentioning beer at all? Should H1 be: H1: The flavor of wort is not dependent on mash pH unless mash pH has been influenced by alkalinity.

We can't begin to design an experiment until you clarify what your hypothesis is. Why won't you do that? Do I seem angry about this?

7.) (repeat the above using a mash pH calculator adjusting mash pH with phosphoric or baking soda but not boil start pH) After 6 weeks do triangle tests on each style

Do you have any idea what it takes to do a meaningful triangle test?

 

[ajdelange]

I'm strongly of the opinion that homebrewers worry way too much about, and fuss way too much with water treatment.
(NOTE: I'm even more strongly of the opinion that you should do whatever you enjoy when pursuing a hobby, so if fussing too much with water treatment is what you enjoy, CARRY ON!)

the second point nullifies the first. I agree with both points, though.

I am a big advocate of using pH strips instead of pH meters. For mashing, I use the pH 4 to 7 strips. Here's why:

1. pH strips are accurate enough. +/- 0.1 pH unit simply does not make a significant difference.

Were strips as accurate as 0.1 then you might have an argument but they are not. Further to that while 0.1 pH may not make the difference between a good and great beer it is necessary to have sub tenth accuracy in order to assess corrective additions.

2. The accuracy and precision of pH strips are in line with each other. The precision of pH meters far outstrips their accuracy.

Well, no. Laboratory pH meters will typically have a precision of 0.01 or 0.001 and accuracy of 0.01 or so. This is the way a well designed instrument (and not just a pH meter) works. It is able to resolve the noise from its sensor(s) so that that noise can, for example, be 'averaged down'. You want the precision of the meter to be such that the error in its reading is controlled by the buffer uncertainty, not the quantizing noise of the meter.

I see people here reporting pH to two significant digits, and depending on my mood I either roll my eyes or laugh out loud.

even when they are doing stability checks?

3. pH strips are cheap.

Can't debate that!

4. pH strips are foolproof.

Not so sure I agree with that. I once helped Kai with some testing he was doing on pH strips. I found that the the continuum of colors on the package label was parallel to but not that close to the continuum of colors produced by the strips.

I'm confident that AJ DeLange and a couple others here can properly calibrate and use a pH meter.

Guilty as charged.

How important is it? I think it's important to be in the right range, but if you've got reliable water and you're in range every time you check, then you will probably be OK if you "forget" a time or two.

If you brew the same beer over and over with the same materials I think you will eventually be able to put your pH meter on the shelf and leave it there. My geeky nature prevents me from doing that.

 

[corax]

I wish your conjecture was true.

I think you overstate the color confusion. Good strips (eg, ColorpHast) are not that hard to read, even in highly-colored wort. But I suppose that if all one brews is Russian Imperial Stout, caution is advisable.

Obviously price is debatable. I don't think 33 cents a pop is that expensive, but YMMV.

Good point about the (otherwise insignificant) hundredths being a good indication of read stability. Would that everyone used it that way.

Regarding ionic strength -- is that not also a concern for electronic meters?

 

[hopjuice_71]

There are a dozen or so "mashing enzymes" (list in Charlie B's paper - my thanks to cire too for posting that) but are there not thousands of others that are involved in the myriad other metabolic pathways that produce beer flavors (what I am concerned with here). Also consider the following reaction which should be familiar: CH3CHO + NADH + H+ <--> CH3CH2OH + NAD+. Obviously it doesn't take place in the mash and I use it because it is familiar and I can't site any specific similar reaction which does take place in the mash but isn't it reasonable to assume that there must be some similar (redox) reactions going on? The point here being that this is an enzyme catalyzed reaction. Supposing the enzyme's activity to be completely flat from DC to daylight the reaction is still clearly pH dependent (especially interested in hopjuices comment on this).

I did some poking around on this today and it was interesting. Regarding the pH optima, the references cited by Bamforth in that table are a dogs breakfast of quite solid studies to "OMG, they published this?" Most, but not all, of the carbohydrate processing enzymes (12 on that list) were OK studies and had generally wide pH profiles, much like the amylases. Harder to tell with the other enzymes - I either couldn't get the paper or they were not so well done. So, I can't honestly comment on efficiencies of ALL the enzymes over a wide pH range. However, I note that Bamforth says this in that pH article: "Another important note is that most enzymes display considerable activity either side of their pH optimum. Provided they survive long enough in the mash, they may be able to complete their job even when not operating at pH optimum." This is reasonably consistent with concept of running pretty efficient mashes over a wide pH range. I would even be willing to wager that that you could go to even some pretty wild pHs for the mash, like say 7, and get decent conversion if you waited long enough. Once again, however, I reserve making any judgement on what the quality of the final beer might be.

Regarding the redox type reactions (*warning more science*), I know nothing about redox enzymes that are particular to mashing. We have worked on a few NAD(P)+ -dependent enzymes and they have had >~80% activity over a pH span of ~2 pH units. Others I have seen in the literature have have up to a whopping 4 pH unit span. So, yes, these types of enzymes are also pH dependent. However, not in the I way I think you are thinking. If I read your message correctly, you seem to be implying that H+ is a reactant and therefore its concentration, as determined by the pH of the bulk buffering system, would be factor in the rate the reaction would occur, regardless of any other enzyme specific factors? I.e. the reaction you have written would be limited at high pH solely due to limited free protons. Am I correct in my interpretation?

Though we see enzyme catalyzed reactions written exactly as you have written yours, the mechanistic reality of how the reactions actually occur on the enzyme is much different. For example, enzyme catalyzed reactions that require protons, like yours, often use a proton shuttle, where a proton, or sometimes multiple protons, are lined up on one or more ionizable amino acid side chains near the protein active site, waiting to be delivered to the reaction (or taken away as the case may be). It is really the pKas of the ionizable groups that determine the availability of protons for the reaction, not the concentration of protons in bulk solvent. An amino acid side chain whose pKa is tweaked by its protein environment to be sufficiently basic will be able to nab protons from water even at a high-ish pH. Water will (almost) always be at a higher concentration than substrates so the protons are never limiting. Whether this is case with redox enzymes in mashing, I don't know. Did this get at your point? I'm not entirely sure if I addressed it properly.

For the record, I am an average home brewer and I can calibrate a pH meter

 

[ajdelange]

Regarding ionic strength -- is that not also a concern for electronic meters?

Yes. A term derived from the log of the ionic strength is added to the pH (or subtracted from the pH of each acid) thus making an acid appear to be stronger than it is. Ionic strength is influenced only by charged ions. In brewing while the wort may have grams of sugar dissolved per liter there are not that many charged species and the ionic strength is low enough that it can be neglected (except by real nitpickers).

 

[corax]

I see people here reporting pH to two significant digits, and depending on my mood I either roll my eyes or laugh out loud.

even when they are doing stability checks?

Well there you go. It depends on who is doing the checking, and with what instrument they are doing it. You or Martin on your carefully calibrated, lab-grade meters? Sure. Bubba on the used pen-type meter he got for 20 bucks on Ebay, and calibrates once a year with 10-year-old standard buffers? Less so.

My main point is that the accuracy, cost, and ease of use of pH strips much better matched to the average homebrewer than those of pH meters are.

 

[Silver_Is_Money]

The importance of mash pH is diminished by our general lack of understanding as to what pH target to choose, when to sample for it, and at what temperature should we read it. Perhaps the full import of pH measurement has yet to be determined because much confusion surrounds the methodology of it.

 

[ajdelange]

This is reasonably consistent with concept of running pretty efficient mashes over a wide pH range. I would even be willing to wager that that you could go to even some pretty wild pHs for the mash, like say 7, and get decent conversion if you waited long enough.

Again I emphasize that I am not really interested in conversion but rather the 'bright flavors' that many seem to think mashing in the proper pH range grant.

Once again, however, I reserve making any judgement on what the quality of the final beer might be.

I think that this says you are willing to allow that there might be some pH dependent things going on in the mash that might effect the beer quality. Is your inclination at this point in the discusion that this is likely, unlikely or very unlikely? I'm not trying to force you into one of those three choices so answer any way you want.

Regarding the redox type reactions (*warning more science*), I know nothing about redox enzymes that are particular to mashing. We have worked on a few NAD(P)+ -dependent enzymes and they have had >~80% activity over a pH span of ~2 pH units. Others I have seen in the literature have have up to a whopping 4 pH unit span. So, yes, these types of enzymes are also pH dependent. However, not in the I way I think you are thinking. If I read your message correctly, you seem to be implying that H+ is a reactant and therefore its concentration, as determined by the pH of the bulk buffering system, would be factor in the rate the reaction would occur, regardless of any other enzyme specific factors? I.e. the reaction you have written would be limited at high pH solely due to limited free protons. Am I correct in my interpretation?

I havn't the temerity to comment on the rate (way out of my depth here). I was, thus, thinking about the extent. But yes, that's what I was thinking. When I used to assay alcohol at very low levels I used a kit in which NAD+ was mixed, in a buffer, with the sample and the absorption of the NADH produced measured. This put into my head that the reaction must be dependent on pH.

Though we see enzyme catalyzed reactions written exactly as you have written yours, the mechanistic reality of how the reactions actually occur on the enzyme is much different. For example, enzyme catalyzed reactions that require protons, like yours, often use a proton shuttle, where a proton, or sometimes multiple protons, are lined up on one or more ionizable amino acid side chains near the protein active site, waiting to be delivered to the reaction (or taken away as the case may be). It is really the pKas of the ionizable groups that determine the availability of protons for the reaction, not the concentration of protons in bulk solvent. An amino acid side chain whose pKa is tweaked by its protein environment to be sufficiently basic will be able to nab protons from water even at a high-ish pH.

Is this really different from what happens in when say H2PO4- and HCO3- are mixed? Protons stored on the monobasic phosphate get transferred to the bicarbonate. The extent of the reaction depends on the pKs (which might be shifted by adding CaCl2, for example) but still depends on the pH. Are you saying that Chatellier does not apply to reactions like this one?

Did this get at your point? I'm not entirely sure if I addressed it properly.

Not sure I understand it but I think I do. Thanks.

 

[RPh_Guy]

From personal experience and from published data from Kai, pH strips are quite inaccurate.

Lots of good discussion here sans the hotdog trolling. Thanks guys.

 

[corax]

From personal experience and from published data from Kai, pH strips are quite inaccurate.

http://braukaiser.com/wiki/index.ph...st_strips_for_pH_measurements_in_home_brewing

Interesting! And strange that the beer measurements are accurate, but not the mash measurements. Is it the difference between beer and wort, or does the accuracy fall off with increasing pH?

OK, I'll take back the accuracy claim. (But I still probably won't shell out for a pH meter!)

 

[lump42]

On a side note. A couple of years ago there was a thread asking about inexpensive pen type meters. Back then it was generally that they are unreliable and you need to buy a good, approximately $100 meter or you are wasting your time or they would be too inaccurate.

Anyone find a good one for less than $50?

Just saw this in the Williams Brewing catalog yesterday. pH meter with a replaceable probe. It looks like a rebranded oakton.

https://www.williamsbrewing.com/Beverage-Doctor-pH-Meter-P4594.aspx

 

[hopjuice_71]

I think that this says you are willing to allow that there might be some pH dependent things going on in the mash that might effect the beer quality. Is your inclination at this point in the discusion that this is likely, unlikely or very unlikely? I'm not trying to force you into one of those three choices so answer any way you want.

After poking around and not finding evidence either way I'm forced to be agnostic about it. So, absolutely there may be other stuff happening at specific mash pHs. But it means I'm also willing to consider that there may be nothing else interesting happening and the importance of mash pH is more about carrying through the pH to final product. This may or may not get resolved by a study or set of studies that I missed or a future study. For the time being, I'll be going with a standard mash pH.

Is this really different from what happens in when say H2PO4- and HCO3- are mixed? Protons stored on the monobasic phosphate get transferred to the bicarbonate. The extent of the reaction depends on the pKs (which might be shifted by adding CaCl2, for example) but still depends on the pH.

Given you have said this, which is largely the same concept, I am thinking I may not have understood your original question correctly and got myself down the rabbit hole of proton shuttles. Bottom line, in my experience, redox enzymes performing reactions similar to that you wrote are pH dependent. We won't worry about why. If redox enzyme are present in barley these reactions may be going on at mash pH, or they may not, I don't know. How was that for not being helpful?

 

[ScrewyBrewer]

All I know is the times I’ve measured the pH of my finished beer it was in the 4.2 to 4.5 pH range. I’ll admit I’ve never recorded or taken beer pH measurements more than a couple of times.

But I believe a beer mashed in the 5.2 to 5.6 pH range will end up finishing in the 4.2 to 4.5 pH range on its own.

 

[ajdelange]

How's this for a coincidence? My son got me an old James Bond movie (Moonraker) out of the bin at Walmart. The bad guys have a secret laboratory hidden in a palazzo in Venice where they make deadly nerve gas. But what does the sign on the laboratory door say? Enzyme Activity Testing!

 

[ScrewyBrewer]

How's this for a coincidence? My son got me an old James Bond movie (Moonraker) out of the bin at Walmart. The bad guys have a secret laboratory hidden in a palazzo in Venice where they make deadly nerve gas. But what does the sign on the laboratory door say? Enzyme Activity Testing!

Haha... I never heard which pH range James Bond favors for his enzymes. But I never heard anyone complain about their beer after hitting their preferred mash pH either.

 

[sixhotdogneck]

Lots of good discussion here sans the hotdog trolling. Thanks guys.

Not trolling at all. Go f-*-c-k yourself.

It's hard to present and test a new concept or idea. I'm sure a bunch of grad/undergrad students wouldn't mind helping.

 

[kh54s10]

This provoked a lot of response that is way above my grade level. And lots of great information. Thanks everyone, even those at the polar ends of the conversation.

I split the vote options in that pH is very important = the first two. 20 votes for 47.6%
And that pH is not critical as the last 3 options. 22 votes for 52.4%

I am at a point where I want to know the pH and see for myself how much difference it makes. I suspect with my palate, and my successes without concerning myself with pH that it will not be dramatic. I also don't want to spend the money, at this time, on a meter, storage solution, and calibration solutions etc. I am sure that I will in the future. Since I really like the majority of the beers that I make I feel I can better invest my money elsewhere at this time.

 

[Silver_Is_Money]

To avoid any other process variables it would require convincing a large brewery on the order of Anheuser-Bush to make large lot runs of beer mashed at (room temperature measured) 5.1, 5.4, and 5.7 pH, put 2 of each into each 6-pack, identified only as red, blue and yellow (by label color) and then have the (completely unaware with regard to the process or ingredient difference) public vote on which label color beer they think tastes the best. Only breweries at that level can control all of the other process and ingredient variables to the degree that they will not statistically influence (as in taint) the flavor outcome. Amateurs would not be able to do this. And the brewery may benefit from an improvement to their product (and thereby sales) at the same time. With the right mass market advertising promotion, the color labeled beer would likely fly off the shelves. Everyone would want to help the brewery improve their beer to the mutual benefit of all.

 

[Silver_Is_Money]

This provoked a lot of response that is way above my grade level. And lots of great information. Thanks everyone, even those at the polar ends of the conversation.

I split the vote options in that pH is very important = the first two. 20 votes for 47.6%
And that pH is not critical as the last 3 options. 22 votes for 52.4%

Only the last two choices believe there is no benefit. The "It might make my beer better" group should be separated out. Then the count is:

mash pH is important: 47.6%
mash pH is not important: 26.2%
mash pH may or may not be important 26.2%

But for most of us this represents only our belief. Not any actual reality.

 

[sixhotdogneck]

To avoid any other process variables it would require convincing a large brewery on the order of Anheuser-Bush to make large lot runs of beer mashed at 5.1, 5.4, and 5.7 pH, put 2 of each into each 6-pack, identified only as red, blue and yellow (by label color) and then have the (completely unaware with regard to the process or ingredient difference) public vote on which label color beer they think tastes best best. Only breweries at that level can control all of the other process and ingredient variables to the degree that they will not statistically influence (as in taint) the flavor outcome. Amateurs would not be able to do this.

As long as the starting boil pH was adjusted to a standard it wouldn't make a difference what their mash pH was... well that's the hypothesis anyway.

 

[Silver_Is_Money]

As long as the starting boil pH was adjusted to a standard it wouldn't make a difference what their mash pH was... well that's the hypothesis anyway.

Too many chefs spoil the soup.

 

[sixhotdogneck]

Too many chefs spoil the soup.

Brewing the beers in #82 myself and then having a bunch of wort and beer tasters (students) would be ok.

 

[ajdelange]

It's hard to present and test a new concept or idea.

This looks like an admission (finally) that this is something that you have made up out of whole cloth. But let's give you the benefit of the doubt and assume that your intent is to proselytize rather than deceive.

Not trolling at all.

I'm not so sure about that. You have consistently presented your ideas as fact. For example...

Truth generally stands on its own. I have no need to engage in vitriolic discussions. Try it for yourself and report back.

Certainly looks like trolling to me. But then I recall a guy who responded to something I posted in another forum that readers should ignore what I wrote because he had a new quantum physics that debunked all that old stuff. His approach was quite similar to yours. So maybe you do sincerely believe what you say but if that's the case why won't you tell us why you believe it? And it's definitely at least unethical to present a hypothesis as fact.

I'm sure a bunch of grad/undergrad students wouldn't mind helping.

They probably would mind because while (male) students' interest in any investigation or course of study is enhanced when beer is involved you can't even coherently state the hypothesis you want to test.

 

[sixhotdogneck]

This looks like an admission (finally) that this is something that you have made up out of whole cloth. But let's give you the benefit of the doubt and assume that you intent is to proselytize rather than deceive.

I'm not so sure about that. You have consistently presented your ideas as fact. For example...


Certainly looks like trolling to me. But then I recall a guy who responded to something I posted in another forum that readers should ignore what I wrote because he had a new quantum physics that debunked all that old stuff. His approach was quite similar to yours. So maybe you do sincerely believe what you say but if that's the case why won't you tell us why you believe it? And it's definitely at least unethical to present a hypothesis as fact.

They probably would mind because while (male) students' interest in any investigation or course of study is enhanced when beer is involved you can't even coherently state the hypothesis you want to test.

I'm pretty sure I've spoken what I believe to be good, true, right and correct with no malice towards anyone. If you see otherwise, then so be it.

 

[kh54s10]

Only the last two choices believe there is no benefit. The "It might make my beer better" group should be separated out. Then the count is:

mash pH is important: 47.6%
mash pH is not important: 26.2%
mash pH may or may not be important 26.2%

But for most of us this represents only our belief. Not any actual reality.

I wouldn't put the second to last (my beers are good so I don't measure) in the category of there is no benefit. I divided in 2 groups because they might not take readings but still may think it would improve their beers. I fit in that category. My internal debate is the degree of improvement, when is the right time for me to get into adjusting for pH? etc. I have other things I would like to spend my money on that may or may not have a greater impact on my beers.

 

[ajdelange]

As long as the starting boil pH was adjusted to a standard it wouldn't make a difference what their mash pH was... well that's the hypothesis anyway.

Ooops! That got posted while I was typing. In any case we now have a hypothesis and can talk about designing a test! We do note that you are calling it a hypothesis here as opposed to a fact. Does this mean you are backing off from your apparent previous position that it is fact? And yet one more request to share with us how you formed this hypothesis.

 

[ScrewyBrewer]

I also don't want to spend the money, at this time, on a meter, storage solution, and calibration solutions etc. I am sure that I will in the future. Since I really like the majority of the beers that I make I feel I can better invest my money elsewhere at this time.

Completely understandable. I view brewing water properties as the 'final frontier' of beer brewing. And something I became interested in only after feeling I had mastered other advanced brewing processes.

 

[ScrewyBrewer]

I'm pretty sure I've spoken what I believe to be good, true, right and correct with no malice towards anyone. If you see otherwise, then so be it.

@sixhotdogneck the last time I checked this thread is in the 'Brew Science' forum. A place where serious debate is welcome as long as it's based on fact. Not baseless conjecture. As of this writing I consider AJ's latest 'Voltmeter' version one of my prized possessions. One that I've just begun to scratch the surface on understanding fully.

The thoughts you present are outside the mainstream not based on previous work or backed up by hard documentation. Causing a lot of background noise to what started as enjoyable and interesting thread on the science of brewing beer.

 

[sixhotdogneck]

Ooops! That got posted while I was typing. In any case we now have a hypothesis and can talk about designing a test! We do note that you are calling it a hypothesis here as opposed to a fact. Does this mean you are backing off from your apparent previous position that it is fact? And yet one more request to share with us how you formed this hypothesis.

If brewing water calculators come up with one answer and the pH of the mash varies over the period of the mash, the answer made by the calculator is only correct once during the course of the mash, unless the pH of mash fluctuates like an accordion. The only pH to carry over to the next process is the one at the end of the mash, i.e. the start of the boil. Given the exbeeriments that found no correlation between a low mash pH and final beer quality and a high mash pH and final beer quality it would be reasonable to assume that the yeast are taking control and of course they take control at the point of the end of boil whose pH is a product of the starting boil pH.

Statistical correlation between calculator results and mash pH measurements appear to be random as the pH of the mash varies over time and no standard has been established that determines at what point in time the pH of the mash should be measured. The calculator by contrast is computing and operating off of the chemical equilibrium point. The point of chemical equilibrium would be assumed to be at the end of the mash, i.e. the start of the boil at which point another series of reactions may occur.

Given the exbeeriments mentioned earlier, there was no significant preferred taste difference between the low and high mash pH variables, which one would expect were there significant differences in amylase enzyme activities or for that matter any of the extraneous enzymes involved in the mash.

 

[ajdelange]

I'm pretty sure I've spoken what I believe to be good, true, right and correct with no malice towards anyone. If you see otherwise, then so be it.

As I said, I'm not sure but you must (and should) understand why your approach in presenting your new idea has caused at least two member's here to conclude you are a troll and me to suspect you are. The frequent implication that your hypothesis is fact, your consistent refusal to acknowledge that your hypothesis is indeed a hypothesis, and your refusal to explain the basis for your hypothesis are certainly legitimate reasons for people to conclude that you are either a troll or a wild eyed prophet of a new religion. I'm willing to extend the benefit of the doubt but you must appreciate that if people are to have any confidence in what you are saying to the point where they are going to support you in testing, it isn't enough that you believe your hypothesis to be 'good, true, right and correct'. You must have something to offer them to suggest that your hypothesis is a reasonable one i.e. that it is one worth testing. I know you aren't a scientist but you still need to understand that an untested hypothesis cannot be called 'correct'. It is only a hypothesis. The fact that you believe it to be correct does not make it correct and your faith isn't enough to convince reasonable people. They need to see a rational basis for your belief.

But enough for the philosophy. Let's talk about the test.

The hypothesis to be tested is
H1: Mash pH has no effect on the quality of finished beer when the pH of the boil is controlled
in which case the null hypothesis is
H0: Mash pH has an effect on the quality of finished beer when the pH of the boil is controlled.

Now it just sort of bothers me to have the phrase "no effect" in the alternative hypothesis so I'd propose reversing the labels:

H0: Mash pH has no effect on the quality of finished beer when the pH of the boil is controlled
H1: Mash pH has an effect on the quality of finished beer when the pH of the boil is controlled.

The approach then ostensibly is to make several worts using a base malt with a high DI mash pH. One wort would not be acidified. The others will be acidified to lower pH's. Now I think we are in trouble. The alternative hypothesis says that mash pH has an effect on finished beer quality. Though everyone says that's the case that isn't what those of use that say that have observed at all. What we have observed is that beers brewed with controlled mash pH taste better i.e. that better results are correlated with mash pH. Perhaps the thing that made that first pilsner in which I controlled pH so much better than any I had made before was not the fact that the mash pH was lower but that it was lowered with Sauermalz.
So we really have to change the hypotheses again to

H0: Mash pH is not correlated to the quality of finished beer when the pH of the boil is controlled
H1: Mash pH is correlated to the quality of finished beer when the pH of the boil is controlled.

I'm kind of stuck here. Clearly a wort acidified to a certain level with black malt is going to be detectably different from one acidified with sauermalz is going to be different from one acidified with phosphoric acid. Shall we just use phosphoric acid as it is most flavor neutral and try to tag pH as the causative agent? Or use other means to just look for correlation?

 

[ajdelange]

A place where serious debate is welcome as long as it's based on fact. Not conjecture.

I think conjecture is OK. I have a problem with baseless conjecture, though. Now that he has finally provided some of his thinking I believe we have to drop the baseless conjecture charge. That does not mean I accept his reasoning as sound though but I haven't looked at it carefully. It is not wise to draw any conclusions from Xbeeriments (or whatever they are called) as they seem more concerned with lots of pictures than with carefully designed experiments and proper analysis of results. But I do feel we owe the guy a read now that he has given us the opportunity.

 

[balrog]

This provoked a lot of response that is way above my grade level. And lots of great information. Thanks everyone, even those at the polar ends of the conversation...I am at a point where I want to know the pH and see for myself how much difference it makes. I suspect with my palate, and my successes without concerning myself with pH that it will not be dramatic. I also don't want to spend the money, at this time, on a meter, storage solution, and calibration solutions etc. I am sure that I will in the future.

This is where I find myself. I have very soft water, and my beers got better after someone recommended using "Water Crystals" which turned into using CaCl/CaSO4/MgSO4/etc additions using one of those calculator-sheets, which immediately prompted a strong desire to know about pH, like a character from a Dirty Harry movie (I GOTS to know). I'm sure I'll eventually get a meter as the dataphile in me just needs to know.

 

[hopjuice_71]

H0: Mash pH is not correlated to the quality of finished beer when the pH of the boil is controlled
H1: Mash pH is not correlated to the quality of finished beer when the pH of the boil is controlled.

I'm not sure you meant to duplicate your hypotheses (?) In truth, even in the most hard-core science these days a null hypothesis is rarely stated. If you were writing a grant to support this research it would be entirely sufficient to state the hypothesis as:

Mash pH is not correlated to the quality of finished beer when the pH of the boil is controlled.

Based on what I have seen and, notably not seen, in the literature, I think this is a solid, well stated hypothesis. It would be fascinating to see the outcome of testing it.

It is not wise to draw any conclusions from Xbeeriments (or whatever they are called) as they seem more concerned with lots of pictures than with carefully designed experiments and proper analysis of results. But I do feel we owe the guy a read now that he has given us the opportunity.

My opinion is that this is a little unfair to the Brulosophy guys. They take a lot of flack but their experimental design is usually surprisingly decent considering the parameters they have to work with. I could go on to defend the merits of how they are going about things but I do agree that it is not wise to draw conclusions from the experiments, and they fully own this sentiment as well. (But, then again, I don't draw conclusions from peer-reviewed publications either, because this is equally unwise. Proof only exists in mathematics and, sometimes, physics. In other disciplines, data and their interpretation can only support or fail to support a hypothesis, but can never provide proof.) For the record, some of the stuff I saw in the peer-reviewed brewing literature in the last few days was garbage - interpretation of small differences as significant without even an analysis of error (these are the irritating types of things that ultimately get accepted as fact then propagated down the years as such). Personally, I find the Brulosophy experiments entertaining and useful, particularly because they at least provide the data and I can interpret the the statistics myself. Sorry, off my soapbox now. This was not targeted at you ajdelange, more of a general sentiment regarding this hard-core scientists perspective of Brulosophy science.