pH: How important is adjusting for pH

[ajdelange]

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,

So far, so good.

unless the pH of mash fluctuates like an accordion.

Lost me there. If it fluctuates like an accordion (which it doesn't) the prediction would be useless. In any case a calculator isn't the only way to control mash pH. It isn't even the preferred way. The preferred way is with pH meter readings. These are, ideally, made over time.

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.

I'm not sure of the significance of this. The next clock reading after 12:01:05 is 12:01:06. When you turn the heat off in the kettle it cools from 100 °C.

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

I know you are unfamiliar with triangle testing. What the Xbeeriment people did is not triangle testing. It borrows some aspects of it but triangle testing it is not. I won't go into how they deviate as there was a lengthy thread on this last summer. Rather I will point out here that a triangle test of a beer (or anything else) is not a test of the beer. It is a test of the panel! It should be very troubling to you to that the group they empaneled was not able to taste any difference between a beer made with no lactic acid and one made with 12 mL. Now I don't doubt that they could not, with statistical significance (but their statisitical significance numbers were drawn from the triangle test numbers and they weren't doing a triangel test) taste any difference but I don't think the beers would be indistinguishable by a properly selected panel testing under the correct conditions.

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.

The yeast do take control of wort pH for sure (and the one exbeeriment certainly demonstrated that!) but what has that to do with the chemistry that took place in the mash tun and kettle. Do you seriously think the chemistries of those two mashes could be the same?

I'll also note that in the low pH test that the kettle pH's before and after the boil were widely disparate (0.9 pH). If you are going to conclude from this experiment that beer quality is not dependent on mash pH then you must also conclude that it is independent of kettle pH which is, I believe, in direct conflict with your hypothesis.

Statistical correlation between calculator results and mash pH measurements appear to be random

You are using terms you don't fully understand. Correlation is a random variable unless the data being correlated are uncertainty free (e.g. the correlation of a sine wave with a cosine wave is deterministic). But again, a calculator is not the preferred method for controlling mash pH. pH meter readings are.

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.

Properly made pH readings form a time history. The brewer is looking for deviations from the path his experience has taught him will give him a good beer.

The calculator by contrast is computing and operating off of the chemical equilibrium point.

No. The first generation calculators don't, AFAIK, even consider the chemistry. The 2nd Gen ones (one) uses malt characteristics derived at a time beyond which little change is going to occur. This is not the equilibrium point. It is, we hope, close to the equilibrium point were the system chemistry not altered further.

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.

No. It's at the end of the first rest. Steps and decoctions produce the further reactions you speak of. But all this is moot as a calculator only strives to give us guidance on what to do to get a particular mash pH at the defacto standard time of 25 - 30 min post strike. This is valuable information in the sense that it gives us an idea as to whether we can tolerate the amount of black patent we want, for example, but it's real value is in guiding us to make a test mash from which we can determine with greater confidence the amount of acid we will add to the actual brew. In the actual brew we check at each step what the pH is.

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.

I don't think you are going to find much support for your hypothesis base on those clearly heavily flawed exbeeriments. As I noted earlier, red warning lights should have come on as soon as you read them. But then you are hardly the first to be taken in by them. Many are even though they warn you that they are only to be taken for their entertainment value.

Perhaps other have a different view.

What I do see out of all this that may be of interest is to question whether pH is the cause of the correlation drinkers observe between mash pH and beer quality.

 

[sixhotdogneck]

So far, so good.

Lost me there. If it fluctuates like an accordion (which it doesn't) the prediction would be useless. In any case a calculator isn't the only way to control mash pH. It isn't even the preferred way. The preferred way is with pH meter readings. These are, ideally, made over time.

I'm not sure of the significance of this. The next clock reading after 12:01:05 is 12:01:06. When you turn the heat off in the kettle it cools from 100 °C.


I know you are unfamiliar with triangle testing. What the Xbeeriment people did is not triangle testing. It borrows some aspects of it but triangle testing it is not. I won't go into how they deviate as there was a lengthy thread on this last summer. Rather I will point out here that a triangle test of a beer (or anything else) is not a test of the beer. It is a test of the panel! It should be very troubling to you to that the group they empaneled was not able to taste any difference between a beer made with no lactic acid and one made with 12 mL. Now I don't doubt that they could not, with statistical significance (but their statisitical significance numbers were drawn from the triangle test numbers and they weren't doing a triangel test) taste any difference but I don't think the beers would be indistinguishable by a properly selected panel testing under the correct conditions.

The yeast do take control of wort pH for sure (and the one exbeeriment certainly demonstrated that!) but what has that to do with the chemistry that took place in the mash tun and kettle. Do you seriously think the chemistries of those two mashes could be the same?

I'll also note that in the low pH test that the kettle pH's before and after the boil were widely disparate (0.9 pH). If you are going to conclude from this experiment that beer quality is not dependent on mash pH then you must also conclude that it is independent of kettle pH which is, I believe, in direct conflict with your hypothesis.

You are using terms you don't fully understand. Correlation is a random variable unless the data being correlated are uncertainty free (e.g. the correlation of a sine wave with a cosine wave is deterministic). But again, a calculator is not the preferred method for controlling mash pH. pH meter readings are.

Properly made pH readings form a time history. The brewer is looking for deviations from the path his experience has taught him will give him a good beer.

No. The first generation calculators don't, AFAIK, even consider the chemistry. The 2nd Gen ones (one) uses malt characteristics derived at a time beyond which little change is going to occur. This is not the equilibrium point. It is, we hope, close to the equilibrium point were the system chemistry not altered further.


No. It's at the end of the first rest. Steps and decoctions produce the further reactions you speak of. But all this is moot as a calculator only strives to give us guidance on what to do to get a particular mash pH at the defacto standard time of 25 - 30 min post strike. This is valuable information in the sense that it gives us an idea as to whether we can tolerate the amount of black patent we want, for example, but it's real value is in guiding us to make a test mash from which we can determine with greater confidence the amount of acid we will add to the actual brew. In the actual brew we check at each step what the pH is.

I don't think you are going to find much support for your hypothesis base on those clearly heavily flawed exbeeriments. As I noted earlier, red warning lights should have come on as soon as you read them. But then you are hardly the first to be taken in by them. Many are even though they warn you that they are only to be taken for their entertainment value.

Perhaps other have a different view.

What I do see out of all this that may be of interest is to question whether pH is the cause of the correlation drinkers observe between mash pH and beer quality.

Your hypothesis in #123 is close and that's what should be pursued if anyone is interested.

 

[ajdelange]

I'm not sure you meant to duplicate your hypotheses (?)

No didn't. Fixed it.

In truth, even in the most hard-core science these days a null hypothesis is rarely stated.

You've probably concluded that I am rather long in the tooth. That's the way it was taught in the days I went to school and during the time period of my practice. Does the current practice mean that it is obvious what the null hypothesis is from a properly stated alternative hypothesis (maybe it isn't called that any more)? Or does it mean that you no longer test by rejecting the null hypothesis? This is what Wikipedia says in the introduction to their article on hypothesis testing.

A hypothesis is proposed for the statistical relationship between the two data sets, and this is compared as an alternative to an idealized null hypothesis

It is no longer au courant?

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.

A little confused here. This was my null hypothesis.

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.

I did start thinking about how one might do that and ran into trouble right away as noted in No. 88. But now that I know the basis for hotdog's hypothesis I don't think the A.J. Foundation would be willing to write the check for this grant.

My opinion is that this is a little unfair to the Brulosophy guys. ... 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.

I did point that out.

PS: I don't take peer reviewed stuff that seriously any more either. Or rather I view it all with a jaundiced eye.

 

[Silver_Is_Money]

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.

This is why I have proposed taking mash pH samples at the end of the mash. My belief (bolstered by several recent forum members actual experiences) is that early in the mash the measured pH is about 0.2 points lower than at the end of the mash, and what I believe is being witnessed here is mash pH transitioning to "wort pH".

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.

Bingo!

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.

True again, and more reason to take the reading at the end of the mash.

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.

I need to take a closer look at these. My classic Brulosophy complaint used to be that they do a lot of late hop additions, and such may skew any ability to discern malt flavor differences. I'm not sure if that is or is not the case here.

 

[passedpawn]

As long as you're all being civil and on topic, and I don't sense trollish behavior, posts are going to be allowed. Contrarians are people too

HBT is a knowledge base, and its entirety is a living and mutable collection of ideas. I respect the subject experts here, but no one (and no idea for that matter) is above question.

 

[hopjuice_71]

You've probably concluded that I am rather long in the tooth. That's the way it was taught in the days I went to school and during the time period of my practice. Does the current practice mean that it is obvious what the null hypothesis is from a properly stated alternative hypothesis (maybe it isn't called that any more)? Or does it mean that you no longer test by rejecting the null hypothesis? This is what Wikipedia says in the introduction to their article on hypothesis testing.

It is no longer au courant?

Yeah, I should clarify here. If one were teaching the scientific method, your approach is absolutely correct, and it is the way I learned it as an undergrad. In practice, however, science appears to be changing and moving away from that type of formal hypothesis formulation. In over 15 years of sitting on grant panels I have never once seen a null hypothesis used. Granted, these would not include math, physics, or applied science grants, which may be different. Typically, one designs experiments to disprove a singled stated hypothesis. Overall, though, a lot of science is moving away from hypothesis testing entirely and into "discovery-based" science. The human genome project is a great example of this.

A little confused here. This was my null hypothesis.

Yes, that is how I would write the hypothesis - mash pH is not correlated to the quality of finished beer when the pH of the boil is controlled. And I would test it by trying to show that mash pH is correlated to the quality of the finished beer when the pH of the boil is controlled. However, you could also remove "not" and it would make no difference as a thorough experimental design would be identical to test either version. All this being said, I would probably change "quality of" to "properties of the." The concept of beer quality, or how good it is, being so subjective I think it would be really hard to get definitive results. The "properties," however, could be well defined in advance and tested for.

 

[hopjuice_71]

I did start thinking about how one might do that and ran into trouble right away as noted in No. 88. But now that I know the basis for hotdog's hypothesis I don't think the A.J. Foundation would be willing to write the check for this grant.

I wouldn't be writing any cheques either but I still find it an interesting question. hotdog sowed the seeds here but, for my part, the hypothesis was really generated by what appears to be a gap in the literature regarding a direct effect of the mash pH on beer properties vs. the effect of the mash pH simply tracking through downstream processes to a favourable final beer pH (owning to the possibility I missed something, so anybody can correct me here!). Not volunteering to do this but I think the hypothesis could be tested with 3 pairs of matched beers involving two pHs, lets just say 5 and 6 for this mind exercise, and a control batch.

Pair 1: mash one batch at pH 5 and the other at 6. Do not alter the pH after the mash and let beers ride to a final product.
Pair 2: mash one batch at pH 5 and the other at 6. Immediately adjust the pHs of worts in the kettle to pH 5.5 (or whatever pH we think is "optimal"). Let everything ride to a final beery product.
Pair 3: mash two batches, each at pH 5.5 (or whatever pH we think is optimal). Immediately adjust the pHs of one batch in the kettle to 5 and the other to 6. Let everything ride to a final beery product.
Control batch: mash a batch at pH 5.5 (or whatever pH we think is optimal). Do not alter the pH after the mash and let beer ride to a final product.

Don't ask me how one would adjust the pHs without otherwise altering flavours (phosphoric acid or sodium hydroxide?) - there are much more knowledgeable people around here for that - but otherwise the water treatments would have to be identical.

Ideally one would like to have a series of objective parameters that could be measured in the beer, e.g. IBUs, foam stability, pH, colour, etc. Some kind of blinded sensory analysis would be required as well, but I think triangle tests would be out because that would require a testing a crap ton of pairings - at least 6 if each beer is compared to the control. More for internal comparisons. Ya, I'm not doing this.

 

[ajdelange]

This is why I have proposed taking mash pH samples at the end of the mash. My belief (bolstered by several recent forum members actual experiences)

and contradicted by the hundreds of pH measurements I have personally taken and the experience of others. The fact that a few people have had the result you personally believe in does not mean that that belief is true. This is an example of confirmation bias. Disclosure: The bulk of the measurements I have done is on minimashes in the lab and I never went beyond about 40 minutes so that if the mash behaves in what I consider to be a normal manner and then the pH zooms by 0.2 points at the last minute I would have missed it. But I have never seen mash pH creep up by 0.2 in an actual full length brew. I have, in fact, seen it drop

True again, and more reason to take the reading at the end of the mash.

Taking readings throughout the mash is good practice. If you see mash pH rise by as much as 0.2 relative to the quasi equilibrium point (20 - 30 min in) that's an indication of a problem in process (but first suspect the pH electrode has drifted and check that). Same is true if pH drops by that much at end of mash (again suspect the pH meter first). In any case none of this has anything to do with the hypothesis which says that beer quality is independent of mash pH. But the pH when is a reasonable question. The most sensible approach would be to measure when the mash is stable and that would be from 25 minutes on. Could be at any time after that though.

I need to take a closer look at these. My classic Brulosophy complaint used to be that they do a lot of late hop additions, and such may skew any ability to discern malt flavor differences. I'm not sure if that is or is not the case here.

No. The problem here is poor technique and failure to understand that a triangle test tests the panel - not the beer. Were I conducting the test and were I given the resources things would have been done very differently and, I'm supposing (we are talking probablilities here) that the differences would have been detected. A bunch of guys with various levels of tasting experience sitting around a table littered with empty beer bottles and pizza boxes is not the way to conduct a triangle test unless you are interested in determining whether a bunch of guys with variate levels of experience sitting at a table littered with empty beer bottles and pizza boxes can tell the difference. Evidently they can't.

 

[bob1852]

A bunch of guys with various levels of tasting experience sitting around a table littered with empty beer bottles and pizza boxes is not the way to conduct a triangle test unless you are interested in determining whether a bunch of guys with variate levels of experience sitting at a table littered with empty beer bottles and pizza boxes can tell the difference. Evidently they can't.

I would argue that's exactly what Marshall et al. are testing: can a bunch of guys with variants levels of experience sitting at a table littered with empty beer bottles and pizza boxes tell the difference?

After all, the average homebrewers are a bunch of guys sitting at tables littered with empty beer bottles and pizza boxes, who wonder aloud how much mash pH, water chemistry, fermentation temps, etc actually matter.....



I did find this one interesting....
BJCP certified judges didn't do any better in Brulosophy triangle tests than non-BCJP certified participants: http://brulosophy.com/2016/01/21/in...t-xbmt-performance-based-on-experience-level/

 

[Silver_Is_Money]

It doesn't seem as if pizza and other beers than the ones being tested would be conducive of discernment in flavor difference detection.

 

[bob1852]

FWIW, the two XBMT's triangle tests I took, there wasn't pizza.

 

[ScrewyBrewer]

I’ll continue taking and recording my mash pH samples 30 minutes into the mash. Cooled to 75-77F because I’m no fan of paying $57USD for replacement electrodes. That’s my ‘standard’. That’s what my mash pH predictions will continue to be based on. I’ll also ‘state that on the label’ of an upcoming version in an effort to promote standardization.

To be honest I’ve never given kettle wort pH adjustments a thought. Or pH adjustments to kegged beer for that matter. It’s taken me years of making mash pH predictions. Brewing recipes. Recording actual mash pH. Adjusting water properties then brewing the recipe over until being satisfied with the results.

I’m not trying to dispute anyone who has found that boil and beer pH control benefits their beer. In fact I appreciate their sharing this information with us. But adding wort boil and beer pH sampling and corrections into the mix would take me decades.

 

[ajdelange]

I would argue that's exactly what Marshall et al. are testing: can a bunch of guys with variants levels of experience sitting at a table littered with empty beer bottles and pizza boxes tell the difference?

If that's all we care about then the problem is much simplified. One of the tests hotdog mentioned showed that the panel couldn't tell the difference between beers brewed with different pH mash and different kettle pH. Given the circumstances this isn't too surprising and I would have no trouble accepting the hypothesis "Beer quality as perceived by the general public measured by sloppy protocol is not correlated with mash or kettle pH". No testing would be needed to convince me of that.

After all, the average homebrewers are a bunch of guys sitting at tables littered with empty beer bottles and pizza boxes, who wonder aloud how much mash pH, water chemistry, fermentation temps, etc actually matter.....

I don't think those things matter much at all to most for whom "The best beer I have ever tasted is the last beer I brewed". It's to us geeky types who really want to understand how things work that such matters are of interest.

I did find this one interesting....
BJCP certified judges didn't do any better in Brulosophy triangle tests than non-BCJP certified participants: http://brulosophy.com/2016/01/21/in...t-xbmt-performance-based-on-experience-level/

Me too! I think I even found that one could conclude that that finding was statistically significant. And this grants me the opportunity to tell one of my favorite brewing stories (which I've told before here so if you've seen it hit the down key"). A guy in the DC area used to have a party every fall to which he invited the DC area beer cognoscenti - professional brewers, master BJCP judges.... Shortly before this I had been contacted by the aforementioned Dr. Bamforth to see if I would be willing to write the color chapter for one of his many books (this is not a plug - if you buy a copy he gets a check - not me). With some trepidation I said "yes" and shortly after that got a thing from ACS (I think it was) advertising a webinar by Dr. B on the subject of beer color. Given my new assignment I figured I'd better check this out. In his presentation he said that beer color was very important because we taste with our eyes as well as our noses and tongues. Armed with this new knowledge I took a pretty mediocre Vienna I had on tap and filled two growlers with it adding some Sinamar to one. Just enough to raise the color 7 SRM (as I recall). These I took to the party and asked for comments on comparative tasting. I should have written those comments down but I'll bet you can imagine the detail in some of the criticism I got "Well clearly you used more crystal malt in this one but I think you went a bit overboard on the 30L. This is putting the ribes over the top and upsetting the hops balance which you could have compensated for with a bit more chloride"). There was one young lady standing off by herself who asked if she could try. So I gave her the two samples and she carefully tasted both and then announced "Well I really don't know anything about beer. I just came with my boyfriend. I'm sorry but they both taste exactly the same to me."

I never got invited back and one of the guys who I was pretty matey with wouldn't speak to me for over a year (though he now denies this and claims not to remember the episode).

 

[sixhotdogneck]

I wouldn't be writing any cheques either but I still find it an interesting question. hotdog sowed the seeds here but, for my part, the hypothesis was really generated by what appears to be a gap in the literature regarding a direct effect of the mash pH on beer properties vs. the effect of the mash pH simply tracking through downstream processes to a favourable final beer pH (owning to the possibility I missed something, so anybody can correct me here!). Not volunteering to do this but I think the hypothesis could be tested with 3 pairs of matched beers involving two pHs, lets just say 5 and 6 for this mind exercise, and a control batch.

Pair 1: mash one batch at pH 5 and the other at 6. Do not alter the pH after the mash and let beers ride to a final product.
Pair 2: mash one batch at pH 5 and the other at 6. Immediately adjust the pHs of worts in the kettle to pH 5.5 (or whatever pH we think is "optimal"). Let everything ride to a final beery product.
Pair 3: mash two batches, each at pH 5.5 (or whatever pH we think is optimal). Immediately adjust the pHs of one batch in the kettle to 5 and the other to 6. Let everything ride to a final beery product.
Control batch: mash a batch at pH 5.5 (or whatever pH we think is optimal). Do not alter the pH after the mash and let beer ride to a final product.

Don't ask me how one would adjust the pHs without otherwise altering flavours (phosphoric acid or sodium hydroxide?) - there are much more knowledgeable people around here for that - but otherwise the water treatments would have to be identical.

Ideally one would like to have a series of objective parameters that could be measured in the beer, e.g. IBUs, foam stability, pH, colour, etc. Some kind of blinded sensory analysis would be required as well, but I think triangle tests would be out because that would require a testing a crap ton of pairings - at least 6 if each beer is compared to the control. More for internal comparisons. Ya, I'm not doing this.

Chances are it won't be done without a large push from folks with significant resources and/or influence on the right people.

 

[couchsending]

Kunze talks a lot about the effects mash pH has on finished beer. He also refers to adjusting boil pH pre and post. If I was to trust anyone in regards to studies performed on various aspects of brewing he’d be towards the top of the list...

 

[ScrewyBrewer]

Kunze talks a lot about the effects mash pH has on finished beer. He also refers to adjusting boil pH pre and post. If I was to trust anyone in regards to studies performed on various aspects of brewing he’d be towards the top of the list...

Here's another article that talks about mash boil and beer pH. And the influence they have on efficiency color and taste.

"Last but not least the pH of beer also affects its taste perception. A low beer pH results in a crisper more lively beer while a high beer pH is generally associated with a dull flavor perception. But there are limits to how low pH can be before the beer's taste starts to take on sour notes. For all malt beers a pH range of 4.25 - 4.6 [Narziss, 2005] is generally accepted as optimal while adjunct beers can be as low as 4.0 [Kunze, 2007] and sour beers will be even lower. The lower pH of adjunct beers is a result of the lower buffer capacity of the adjuncts. In this case yeast is able to lower the pH further because the beer does not offer as much resistance (buffering) as it does in all malt beers."

 

[mjdonnelly68]

Like a lot of things with brewing, I think that pH has an impact but much less impact than we assume. I believe its a classic example of correlation not causation. Brewers who's beers are great may obsess over their pH (or water, or mash temps etc) but their beers are not great because of their pH (or water, or mash temps etc). Their beer is great because they obsess over their process. That focus is what makes the beer great, not exclusively what is focused on. That being said, I religiously measure my pH...

 

[ajdelange]

Like a lot of things with brewing, I think that pH has an impact but much less impact than we assume.

I'd ask you the same question I have asked before in this thread several times. If its impact is so small why do breweries waste so much effort on controlling it and testbook authors so much space to describing how to control it?

I believe its a classic example of correlation not causation.

Could be but pH is referred to, by water chemists, as "the master variable". It sets the charge on anything ionizable in the mash, thereby changes the shape of proteins, controls the extent to which acids and bases dissociate, the extent to which many redox reactions proceed etc. It seems reasonable to me, therefore, that it is going to have an effect on chemistry of mash just as it does on other systems (what happens to you if your serum pH gets outside that ± 0.1 pH band?).

 

[Silver_Is_Money]

In 1909 a guy named S. P. L. Sørensen invented the pH scale while working as an employee at the Carlsberg Laboratory in Copenhagen.

J. P. Jacobsen, the same man who founded the Carlsberg Laboratory also founded the Carlsberg Brewery. Is there a connection to be made here? As in, was the pH scale itself invented specifically so the Carlsberg Brewery could brew better beer?

Subtle hint, the answer is a resounding "YES".

 

[ajdelange]

Broadly speaking yes but in particular, no. Jacobsen founded the laboratory to do general research but was, of course, hopeful that many of the things that came out of it would benefit his brewery. Sørenson was interested in the protein chemistry of (and this is the part I'm not sure I'm remembering right) oncogenesis. Of course pH is a keystone in many branches of chemistry. The only thing more prevalent in the universe than hydrogen is ignorance.

 

[Kee]

. . .I would have no trouble accepting the hypothesis "Beer quality as perceived by the general public measured by sloppy protocol is not correlated with mash or kettle pH".

I don't think those things matter much at all to most for whom "The best beer I have ever tasted is the last beer I brewed". It's to us geeky types who really want to understand how things work that such matters are of interest.

. . . I took a pretty mediocre Vienna I had on tap and filled two growlers with it adding some Sinamar to one. Just enough to raise the color 7 SRM (as I recall). These I took to the party and asked for comments on comparative tasting. I should have written those comments down but I'll bet you can imagine the detail in some of the criticism I got "Well clearly you used more crystal malt in this one . . .

So are we just stuck with "beer tastes good" (or "bad" or "great") is subjective, and leave it at that?

 

[ajdelange]

Trying to put all this in perspective it appears that we have a new hypothesis in brewing:

Hnew: The quality of finished beer is not correlated to mash pH when the pH of the boil is controlled.

It stands against the currently accepted hypothesis

Hold: The quality of finished beer depends on mash and kettle pH to the extent that it is worth controlling both.

How do readers of this thread decide whether there is any liklihood that the new hypothesis is valid to the point that they might consider changing their brewing practices? The nerdy guys (I am one in case you all haven't noticed) want to do a test. I don't believe we can realistically hope to do that. For starters we don't have a definition of "quality". Hopjuice has indicated that it would be great if we had some objective measures and we do but while some readers here might consider foam stability (which we can measure but not very repeatably or precisely) an indicator of quality it might be completely unimportant to someone else relative to, say color (which we can measure precisely though few do) or 'Bright flavors'. To test Hnew we must have a precise definition of "quality". As there are an infinite number of ways to define high quality we clearly have a big problem here.

So perhaps we need to reword Hnew to

Hnew1: Beers identical to one another except for mash pH are indistinguishable from one another as long as the kettle pH's are the same.

We can at least think about triangle tests now but we still have lots of problems - all those that go with triangle tests. Remembering, as few do, that a triangle test is a test of the panel, not the beer, we have to ask "Indistinguishable by whom?" Most people? Beer afficionados (who scored higher than trained BJCP judges)? Super tasters? One guy? How do we make beers identical to one another but with different pH? What is the range of mash pH difference over which we need to test? One pH unit or 0.4 pH unit? Is Hnew perhaps valid for Pilsners but not for Wheat Beers? What kettle pH should we set? The number of tests is multiplying fast. The matrix is too big. And we haven't even addressed "better/worse" yet. Is it possible that setting mash pH in the traditional way followed by a kettle adjustment results in a beer worse than one in which kettle pH is allowed to go where it will naturally? Does this depend on beer style?

Thus it doesn't look to me as if we can conceive of any testing to lead us to acceptance of Hnew. Hold is pretty close to being the alternative hypothesis to Hnew. Can we do tests to reject Hnew and thus move towards acceptance of Hnew? No, and for all the same reasons that applied to Hnew. But there is some information out there about Hold. It is not based on robust laboratory testing but on the simple empirical observation that breweries have been acting as if Hold were valid since the day centuries ago when Hans accidentally let some mash sour, used it anyway and found it made better beer. Thus there is some support, in fact quite strong support, for Hold. Is there any similar for Hnew? It is based on two exbeeriments one of which in addition to demonstrating that a panel couldn't tell the difference between beers brewed at different mash pH's also demonstrated that they couldn't tell the difference between two beers brewed at different kettle pH's. Thus I feel that there is much more support for Hold than Hnew.

Now if someone for whatever reason feels that perhaps there is some validity to Hnew there is nothing stopping him from brewing beer on its basis and he should do that. The only thing that really counts to the reader of this forum is whether in the opinion of that brewer the new hypothesis leads to beer of higher quality than the old. The definition of quality is entirely determined by the brewer and not by some group of guys with their own ideas about what is good.

 

[ajdelange]

So are we just stuck with "beer tastes good" (or "bad" or "great") is subjective, and leave it at that?

I kind of think so. See the post following yours that I was typing while you were posting this. Perception of good or not so good is a very subjective thing. It takes place not on the palate but in the larger organ located behind and a bit above it. That little anecdote illustrates that quite clearly I think. As does this one:

I had a bunch of people from my club over to do a multiple of 5 years club anniversary brew. Needless to say the activities were not limited strictly to brewing. My brewing notebook was out on the table and one of the guys started paging through it and found a scoresheet he'd submitted for the beer he was drinking and commented that he couldn't believe the unfavorable comments he'd put on the scoresheet given how great the beer he was drinking was. The first time he encountered that beer he was looking for a way to reject it. The second time his interest was in having a good time with his friends and enjoying the free (always tastes better) beer on tap. Is it surprising that his perceptions of the beer were different?

 

[Kee]

. . . The first time he encountered that beer he was looking for a way to reject it. The second time his interest was in having a good time with his friends and enjoying the free (always tastes better) beer on tap. Is it surprising that his perceptions of the beer were different?

That makes sense.

 

[mjdonnelly68]

I'd ask you the same question I have asked before in this thread several times. If its impact is so small why do breweries waste so much effort on controlling it and testbook authors so much space to describing how to control it?

Could be but pH is referred to, by water chemists, as "the master variable". It sets the charge on anything ionizable in the mash, thereby changes the shape of proteins, controls the extent to which acids and bases dissociate, the extent to which many redox reactions proceed etc. It seems reasonable to me, therefore, that it is going to have an effect on chemistry of mash just as it does on other systems (what happens to you if your serum pH gets outside that ± 0.1 pH band?).

I'm not assailing the importance of pH or water chemistry - they both play a signifiant part in beer quality and consistency . I think that's a big reason why commercial breweries measure and control to the degree they do - their product needs to be of high quality and mirrored consistency. Only way to make exactly the same beer batch after batch at that scale is to diligently measure and control for all things that impact the finished beer.

I was referring only to the home-brew plane. For batch to batch brewers, I think there are plenty of other things that have a greater impact on the quality of our results and an exact consistency batch to batch is not attainable.

 

[mabrungard]

I was referring only to the home-brew plane. For batch to batch brewers, I think there are plenty of other things that have a greater impact on the quality of our results and an exact consistency batch to batch is not attainable.

That's not my experience. There is an incredible amount of crappy homebrew and probrew out there and the major contributor to that is water and pH problems based on my almost 20 years of judging.

The advantage that major brewers have is that they are often brewing the same beer with the same ingredients, day after day. They also tend to combine multiple mashing batches into large fermenters that gives them an additional chance at correcting minor batch variations. It's homebrewers and small craftbrewers tendency to brew a different beer each batch that makes the requirement of figuring out mash chemistry beforehand, much more important.

 

[mjdonnelly68]

That's not my experience. There is an incredible amount of crappy homebrew and probrew out there and the major contributor to that is water and pH problems based on my almost 20 years of judging.

The advantage that major brewers have is that they are often brewing the same beer with the same ingredients, day after day. They also tend to combine multiple mashing batches into large fermenters that gives them an additional chance at correcting minor batch variations. It's homebrewers and small craftbrewers tendency to brew a different beer each batch that makes the requirement of figuring out mash chemistry beforehand, much more important.

All valid points that make perfect sense. I'll humbly stand down and defer to the experts.

 

[ajdelange]

Looking at the top of the page it appears that nearly 3/4 of the respondents take pH measurements in the hope or expectation that it will improve their beers. Is that surprising for the Beer Science Forum? Wonder how the results would compare were this identical poll posted in the All Grain Brewing Forum.

 

[Silver_Is_Money]

One important polling option was left off:

'I don't take (or need to take) pH readings because I use software that confidently leads me to the correct target pH.'

I wonder how many would be honest enough (or should that be deceived or confused enough) to select this option, had it been available.

 

[CTS]

One important polling option was left off:

'I don't take (or need to take) pH readings because I use software that confidently leads me to the correct target pH.'

I wonder how many would be honest enough (or should that be deceived or confused enough) to select this option, had it been available.

Well this is what I'm doing as I don't have a PH meter yet. So I'm using 100% distilled water and bru'n water to get my PH value.

 

[AWildBrett]

Test

 

[passedpawn]

Test

Well, there was a time I could have deleted this. I traded my guns for a rocking chair. No regrets I guess.

 

[dmtaylor]

Test

 

[Die_Beerery]

I don't think you are going to find much support for your hypothesis base on those clearly heavily flawed exbeeriments. As I noted earlier, red warning lights should have come on as soon as you read them. But then you are hardly the first to be taken in by them. Many are even though they warn you that they are only to be taken for their entertainment value.

Just popped in to also rag on the tools that are the brucru and their cronies. That is all, carry on.

 

[VirginiaHops1]

I thought the part was funny on page 3 where the poster was touting ph strips and laughing at brewers who tracked ph to 2 decimals with supposedly shoddy meters. Then someone posts one link about ph strips inaccuracy and he/she concedes ok they're very inaccurate but I still won't use them. Gotta love the interwebs where everyone think they're the most clever guy in the room