pH: How important is adjusting for pH

[ajdelange]

You've used a lot of words but haven't said much of anything.

And I note that you haven't responded to any of them other than this comment. If you had a leg to stand on you would be offering your reasons for holding these positions.

In few words: you hold positions that are in conflict with accepted brewing (and other) science. Either you are wrong or the rest of the world is wrong. If the rest of the world is wrong it needs to be set right as a lot rides on this science in many discipllines. Simple enough?

 

[sixhotdogneck]

And I note that you haven't responded to any of them other than this comment. If you had a leg to stand on you would be offering your reasons for holding these positions.

In few words: you hold positions that are in conflict with accepted brewing (and other) science. Either you are wrong or the rest of the world is wrong. If the rest of the world is wrong it needs to be set right as a lot rides on this science in many discipllines. Simple enough?

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

 

[hopjuice_71]

Here again you know something the rest of the world doesn't. It foolishly thinks that enzymes have peak activity in a certain range of pH depending on the enzyme. Here the significance of your discovery has much wider applications than in brewing as workers in many fields (including medicine) are laboring under this misconception. It is essential that the medical community, at least, be made aware of your discovery.

Actually, sixhotdogneck is right here. I am part of that medical (research) community. I also research enzymes that convert polysaccharides, very much like the barley amylases. Enzymes very often have quite broad pH profiles, including those that are medically relevant. Scientists generally pick an estimated "peak" because it simplifies things for the end user; however, enzymes will typically operate quite well over sometimes very large pH ranges (depending on the catalytic mechanism they use). Think about it, an enzyme that has really tight operational parameters will not be a successful tool for an organism in a changing environment. This applies to the internal workings of humans as well.

Specific to the barley amylases, it is quite well documented in the primary literature that they have >90% activity over a pH range of ~4.5-6.5 (some of those authors are colleagues of mine). But, someone, sometime, was forced to pick a "peak," which is really just the centre point of a broad plateau in the pH profile. This pH optimum has persisted in brewing, maybe because on a massive commercial scale a 2% increase in activity translates to cost savings.

 

[Silver_Is_Money]

A lot of people in the homebrew world have made a lot of money on bunk spreadsheets and bunk books in which they make false assumptions and these then get spread throughout the homebrew world gossip chain.

My spreadsheet is both free and complete. There is no free sample hook followed by a full version line and sinker waiting in the wings that will cost you. Over the scant few weeks more than one full year that it has been made publicly available only a grand total of 3 people have contributed small donations in grateful appreciation of my effort, and after the obligatory 7% PayPal cut my net donations to date (spanning a bit more than one year) total to only $23.30. Yet I plod on, always trying hard to improve it and introduce new features and come up with better releases, while knowing full well that of the 2 to 3 people on average per day who will actually download it, right close to no one among them is willing to contribute donations to my effort. I'm always trying to answer questions as to its proper function, and listen to suggestions (both on this forum, and in private emails). And I'm quite often willing to run a forum members recipe through it and let him know my spreadsheets output advice. I've even endured some rather obvious (to me) spammers who rail on against my spreadsheet and its output by passing along clearly false and misleading information in regard to it, with their motives unknown to me, but each of such clearly painful none the less. With me it is a personal compulsion to better the product and bring happiness to the users who may find benefit in it that keeps me motivated, and allows me to endure such abuse. That I make roughly $23 per year for my effort indicates that my motivation to find and offer improvement is clearly not one of financial gain.

 

[sixhotdogneck]

My spreadsheet is both free and complete. There is no free sample hook followed by a full version line and sinker waiting in the wings that will cost you. Over the scant few weeks more than one full year that it has been made publicly available only a grand total of 3 people have contributed small donations in grateful appreciation of my effort, and after the obligatory 7% PayPal cut my net donations to date (spanning a bit more than one year) total to only $23.30. Yet I plod on, always trying hard to improve it and introduce new features and come up with better releases, while knowing full well that of the 2 to 3 people on average per day who will actually download it, right close to no one among them is willing to contribute donations to my effort. I'm always trying to answer questions as to its proper function, and listen to suggestions (both on this forum, and in private emails). And I'm quite often willing to run a forum members recipe through it and let him know my spreadsheets output advice. I've even endured some rather obvious (to me) spammers who rail on against my spreadsheet and its output by passing along clearly false and misleading information in regard to it, with their motives unknown to me, but each of such clearly painful none the less. With me it is a personal compulsion to better the product and bring happiness to the users who may find benefit in it that keeps me motivated, and allows me to endure such abuse. That I make roughly $23 per year for my effort indicates that my motivation to find and offer improvement is clearly not one of financial gain.

I commend you on giving away your efforts.

Now for what I am about to speak Lord forgive me.

Your development methods leave much to be desired. You seem to read a post about some topic that affects the mash pH, you then ask or surmise what would correct that deficiency in your spreadsheet and ask AJ Delange if you're correct or that he validates your assumption. You then "correct" the model in your spreadsheet to account for whatever it is believed to have needed changing and up the version number of your software - continuing the guess/correct cycle.

Guess/correct is not the best way to develop a mash model nor to update software.

 

[MSK_Chess]

great discussion guys, really.

The pH of a solution is a logarithmic measure of the freely available H+ions. The concentration of these ions affects the enzymes in various ways. A change in pH leads to changes in the charges on the enzyme due to the reaction of the H+ ions with the carboxyl or amino functional groups [cuny.edu].

The at high pH (low concentration of H+ in the solution> the carboxyl group disassociates

COOH → COO- + H+
This leaves a negative charge at the site of the carboxyl group and donates a proton* H+ to the solution. This reaction is reversed at low pH

At low pH (high concentration of H+ in the solution) the amino functional group binds a proton*

NH2 + H+ → NH3+
This results in a positive charge on the site of the amino group. A reaction that is reversed at high pH.

These pH dependent reactions determine the electric charges and as a result the shape of the enzyme and its ability to react with the substrate. As a result a pH exists at which the enzyme will be most efficient performing the reaction it was designed for. On either side of that optimum the effectiveness of the enzyme will decline until it is unable to function anymore.

The change in enzyme activity within 2-3 pH units to either side of the optimum is generally a reversible process [lsbu.ac.uk]. This means that no permanent damage is done to the enzyme. It also means that a suboptimal pH in mashing doesn't necessarily damage the enzymes and that the full enzymatic activity can be restored by adjusting the mash pH into the optimal range, except for the enzymes that have already been denatures. A more severe pH change 3+ units is likely to denature the enzyme due to high stress that the extreme change in the charges place on the structure of the enzyme. This basically makes the enzyme less stable and it denatures at a fairly high rate even below its critical temperature. In some cases strong acidity can also hydrolyze the peptide links (i.e. break the amino acid chain the makes up the enzyme).

When considering pH, it should be noted that the pH of a solution changes with temperature. The rate of change is dependent on the solution itself. For wort and mashes the actual pH is 0.35 units lower at 65 C (150F) than at room temperature 20 C (68 F). At 75 C it is 0.45 units lower [Briggs, 2004].

*I think the author means donate an electron, please correct me if I am wrong.
http://braukaiser.com/wiki/index.php/Enzymes

 

[hopjuice_71]

great discussion guys, really.

The pH of a solution is a logarithmic measure of the freely available H+ions. The concentration of these ions affects the enzymes in various ways. A change in pH leads to changes in the charges on the enzyme due to the reaction of the H+ ions with the carboxyl or amino functional groups [cuny.edu].

The at high pH (low concentration of H+ in the solution> the carboxyl group disassociates

COOH → COO- + H+
This leaves a negative charge at the site of the carboxyl group and donates a proton* H+ to the solution. This reaction is reversed at low pH

At low pH (high concentration of H+ in the solution) the amino functional group binds a proton*

NH2 + H+ → NH3+
This results in a positive charge on the site of the amino group. A reaction that is reversed at high pH.

These pH dependent reactions determine the electric charges and as a result the shape of the enzyme and its ability to react with the substrate. As a result a pH exists at which the enzyme will be most efficient performing the reaction it was designed for. On either side of that optimum the effectiveness of the enzyme will decline until it is unable to function anymore.

The change in enzyme activity within 2-3 pH units to either side of the optimum is generally a reversible process [lsbu.ac.uk]. This means that no permanent damage is done to the enzyme. It also means that a suboptimal pH in mashing doesn't necessarily damage the enzymes and that the full enzymatic activity can be restored by adjusting the mash pH into the optimal range, except for the enzymes that have already been denatures. A more severe pH change 3+ units is likely to denature the enzyme due to high stress that the extreme change in the charges place on the structure of the enzyme. This basically makes the enzyme less stable and it denatures at a fairly high rate even below its critical temperature. In some cases strong acidity can also hydrolyze the peptide links (i.e. break the amino acid chain the makes up the enzyme).

When considering pH, it should be noted that the pH of a solution changes with temperature. The rate of change is dependent on the solution itself. For wort and mashes the actual pH is 0.35 units lower at 65 C (150F) than at room temperature 20 C (68 F). At 75 C it is 0.45 units lower [Briggs, 2004].

*I think the author means donate an electron, please correct me if I am wrong.

Thanks for this. Just to amend it a bit *warning science ahead*...

Barley amylases use a double displacement catalytic mechanism. The carboxylate side chain of an amino acid in the enzyme active site acts as a general acid/base in catalysis, another different carboxylate side chain of an amino acid in the active acts as a nucleophile (there are no amino groups involved in catalysis by amylases). The protonation states of the amino acids is key to their participation in catalysis - the acid/base must start the cycle protonated while the nucleophile must start deprotonated. The ascending limb of a pH profile (lower pH side of the maximum), like that posted by MSK_Chess, corresponds to the protonation state of the nucleophile (as defined by its pKa, which is in turn defined by its particular environment in the enzyme). Correspondingly, the descending limb (high pH side of the maximum) represents the protonation state of the acid/base, again defined by its pKa. In fact, the pKas of catalytic residues can be determined by the inflection points of the ascending and descending limbs of pH profiles. A pH below the pKa of the nucleophile or above the pKa of the acid/base and the enzyme is inactive - but not necessarily denatured (most proteins are quite stable between pHs of 3 and 9, regardless of their optimum operating pH). It turns out in the barley amylases, and in the a-glucosidase/amylase family in general, the pKas of the catalytic residues are quite well separated, often by several pH units as in the barley enzymes, giving broad pH profiles with no real maximum.

 

[ajdelange]

I want them doing what they have evolved to do, which is both.

If I have a tree I want cut down I call Kenny. Kenny is very good as a woodsman and he is also perfectly capable of walking here. But I don't want him to. Not only will the job get started faster if he drives but he will have more energy to devote to cutting the tree if he does.

And for the record, I'm not saying I don't pay attention to pH. I just don't worry about it much. The title of the thread asking the question if how important is pH adjustment, my answer would be: "somewhat." It is important enough to know the parameters and get in the ballpark. Not important enough to lose sleep over. I'm way more concerned with yeast health, sanitation, cold side oxidation, water mineral profile, ingredient quality and good old recipe formulation. Cheers.

I have no problem with that approach. Now I will admit that I do lose sleep over mash pH but not because I am worried about my mash pH but rather because I am trying to think of some better way to estimate it or measure the things I need to know to make those estimates. It's just another one of the multiple aspects of brewing that one can find himself interested in and choose to devote his attentions to.

I sort of stumbled onto the beneficial aspects of mash pH control but when I tasted how much better that first pH controlled beer was than any other I had ever brewed I was sold on it. So my perspective on it was derived from that experience and the engineer's natural inclination to want to take the clock apart to see how it works.

 

[ajdelange]

Hopjuice and Chess: Interesting posts but bunk! Enzyme activity is constant until pH exceeds 6.5. That was clearly stated in No. 35.

 

[ajdelange]

At low pH (high concentration of H+ in the solution) the amino functional group binds a proton*
*I think the author means donate an electron, please correct me if I am wrong.

He's right. Look at the dissociation equation

RCOOH <---> H+ + RCOO-

Consider Chatellier's Principle. As you lower pH you are increasing the concentration of H+ and this pushes the reaction to the left. Protons in solution are taken up by RCOO- ions thus forming the acid RCOOH. This is not limited to amino acids nor to the side chains of the enzyme proteins nor to any other proteins in the mash. It applies to all acids in the mash.Just to pick an acid consider succinic acid. It has two pK's 4.2 and 5.6. If the malt has a DI pH of 5.7 and has been mashed in DI water then the mash pH will be 5.7 and the wort will contain a tiny bit of H2Suc, more HSuc- and lots more Suc--. If some lactic acid is added supplying protons the following reactions will occur
Suc-- + H+ --> HSuc-
HSuc- + H+ --> H2Suc

All three succinate species will be present but they will be redistributed in such a way that the overall charge on them is decreased (made more positive) by exactly the number of protons absorbed.

 

[MSK_Chess]

LOL you guys are 2 funny. Hopjuice its a bit beyond my understanding at present even after reading it numerous times, clearly I am way out of my depth but I really do appreciate the effort. I am familiar with the idea of 'donating' electrons, but protons, I have never even come across! so far at least.

 

[MSK_Chess]

He's right. Look at the dissociation equation

RCOOH <---> H+ + RCOO-

Consider Chatellier's Principle. As you lower pH you are increasing the concentration of H+ and this pushes the reaction to the left. Protons in solution are taken up by RCOO- ions thus forming the acid RCOOH.

[/QUOTE]
Hi aj its a concept I am completely unfamiliar with and even if you explained it to me for a thousand years I don't have enough understanding to grasp it, cations and anions I am familiar with and I thought this was what the author was referring to.

 

[ajdelange]

Donating and picking up electrons is usually in the province of redox reactions whereas proton exchange is in that of acid/base reactions.

However we can define a base (Lewis) as an electron pair donor. One of the criticisms of this approach is that it turns acid/base reactions into redox reactions.

I'll bet you can understand proton exchange. First off, what is a proton? It is an atomic particle with the same charge as an electron but with a positive charge of the same magnitude as the electron's. A hydrogen atom is made up of one proton and one electron. In water two hydrogens come into the vicinity of an oxygen atom. Oxygen is more electron hungry that hydrogen so the oxygen pulls the hydrogen atoms' electrons close to it leaving it with a net negative charge and the hydrogen atoms with a net positive one. They are attracted, therefore, to the oxygen and the molecule stays intact. But if something comes along to disturb this tranquil scene one of the hydrogen atoms can get knocked off. It does not take its electron with it, however. The oxygen holds on to it. So we get H2O <--> H+ + OH-; the dissociation of water, Now that H+ is just a hydrogen atom minus its electron IOW a proton.

Where does that proton go? Often it's straight to another water molecule so that the real reaction is H2O + H2O <--> H3O+ + OH-. Other times it goes to another base such as a bicarbonate or succinate ion. Does that help at all?

 

[MSK_Chess]

ok, well that helps, I was unaware, I'll come back in about a thousand years and we shall talk then!

 

[Silver_Is_Money]

I commend you on giving away your efforts.

Now for what I am about to speak Lord forgive me.

Your development methods leave much to be desired. You seem to read a post about some topic that affects the mash pH, you then ask or surmise what would correct that deficiency in your spreadsheet and ask AJ Delange if you're correct or that he validates your assumption. You then "correct" the model in your spreadsheet to account for whatever it is believed to have needed changing and up the version number of your software - continuing the guess/correct cycle.

Guess/correct is not the best way to develop a mash model nor to update software.

There is much truth in this, but the full truth is that I have mainly changed the means by which my software handles the deep roast end of the SRM spectrum, wherein the light to mid SRM's have not been radically altered. I do not have experience in brewing deep roast beers, and I have vacillated between a historical need to have up to 200 ppm alkalinity and A.J.'s contention that such is nowhere near the case in the real world. I've hitched my wagon in regard to robustly dark brews to enough losers that I finally decided to hitch it to a winner.

Along the way I have demonstrated that other of such software as mine has (for one particular recipe I've plugged into all of them) spanned from a need for a bit of acidity all the way to a need for 16.5 grams of baking soda, so my dilemma here is not solely my own. I just happen to be very public and honest and open as to my doings and alterations with regard to my software, and as to my reasoning for same. Others have over the years made radical changes, but the best you can expect to hear from them is generally that a new version is available. And often enough, you don't even hear that.

 

[hopjuice_71]

Hopjuice and Chess: Interesting posts but bunk! Enzyme activity is constant until pH exceeds 6.5. That was clearly stated in No. 35.

To be honest, I interpreted his pH 6.5 comment as referring to the pH above which amylase activity falls off significantly, which would be roughly consistent with the pH profiles of these enzymes. But perhaps I missed something?

 

[ajdelange]

Actually, sixhotdogneck is right here. I am part of that medical (research) community. I also research enzymes that convert polysaccharides, very much like the barley amylases. Enzymes very often have quite broad pH profiles, including those that are medically relevant. Scientists generally pick an estimated "peak" because it simplifies things for the end user; however, enzymes will typically operate quite well over sometimes very large pH ranges (depending on the catalytic mechanism they use). Think about it, an enzyme that has really tight operational parameters will not be a successful tool for an organism in a changing environment. This applies to the internal workings of humans as well.

Specific to the barley amylases, it is quite well documented in the primary literature that they have >90% activity over a pH range of ~4.5-6.5 (some of those authors are colleagues of mine). But, someone, sometime, was forced to pick a "peak," which is really just the centre point of a broad plateau in the pH profile. This pH optimum has persisted in brewing, maybe because on a massive commercial scale a 2% increase in activity translates to cost savings.

Think about what you are saying. There are enzymes that exhibit broad activity peaks of course. Apparently papain is flat over entire range of biological possibility. But hotdog's statement was that enzyme activity is constant until pH 6.5 is reached. How about pH 4. That's below 6.5. Is the activity of alpha amylase the same at 4 as it is at 6? And how about beta amylase? The guys that sell it say its range of peak activity is 4 - 5.5. Is it's activity at 5 the same at 5 as it is at 6.5. And how about beta glucanase. The Enzyme Education Institute says its maximum activity occurs between 3.5 - 6. Is it's activity at 6.5 the same as 5? And what about the myriad of other enzymes in barley malts that catalyze the reactions that produce the flavor aroma and body characteristics we seek? Are their activities flat over the range of possible mash pHs? Clearly no or mashing in a certain range would not result in better tasting beers.

Perhaps because of commercial brewing practices where a 2% yield in extract may have significant impact on the bottom line everyone thinks the goal of pH control is better extract. That isn't the only goal. Better tasting beer is. It is recognized that the pH's goals stated in the literature represent a compromise as we haven't much choice but it's also recognized that best extract yield isn't the only thing coupled to profits. Beer quality has something to do with it.

 

[hopjuice_71]

LOL you guys are 2 funny. Hopjuice its a bit beyond my understanding at present even after reading it numerous times, clearly I am way out of my depth but I really do appreciate the effort. I am familiar with the idea of 'donating' electrons, but protons, I have never even come across! so far at least.

Well, you are not off course here. There is a proton inventory but there is also bonds being broken and formed, which involves a reshuffling of electrons. When we write out the catalytic mechanisms we actually track the electrons with teeny little arrows.

 

[sixhotdogneck]

To be honest, I interpreted his pH 6.5 comment as referring to the pH above which amylase activity falls off significantly

Yes.

 

[ajdelange]

Truth generally stands on its own.

No, it doesn't. It has to be discovered and that's what we try to do here.

I have no need to engage in vitriolic discussions.

We are trying to get you away from vitriolic comments to support your controversial assumptions. You have some reason for thinking that higher pH which results in more dissociation of phenols leading them to be more polar in character is not related to their solubility in a polar solvent: water. That's not generally accepted as true. If you have some reasons for thinking that it is true you should not be afraid to state what they are. For example you might have done some experiments that contradict the conventional understanding. No vitriol needed (unless you used it in your experiments).

Try it for yourself and report back.

Reporting back for the fourth (or is it fifth time):
Controlling mash pH improves beer! It's done so for me. It's done do for others here and it's done so for breweries the world around. Again, in the hopes you'll read it this time: why would a world class brewery with very low alkalinity water acidify its mash if there were no benefit?

 

[sixhotdogneck]

Think about what you are saying. There are enzymes that exhibit broad activity peaks of course. Apparently papain is flat over entire range of biological possibility. But hotdog's statement was that enzyme activity is constant until pH 6.5 is reached. How about pH 4. That's below 6.5. Is the activity of alpha amylase the same at 4 as it is at 6? And how about beta amylase? The guys that sell it say its range of peak activity is 4 - 5.5. Is it's activity at 5 the same at 5 as it is at 6.5. And how about beta glucanase. The Enzyme Education Institute says its maximum activity occurs between 3.5 - 6. Is it's activity at 6.5 the same as 5? And what about the myriad of other enzymes in barley malts that catalyze the reactions that produce the flavor aroma and body characteristics we seek? Are their activities flat over the range of possible mash pHs? Clearly no or mashing in a certain range would not result in better tasting beers.

Perhaps because of commercial brewing practices where a 2% yield in extract may have significant impact on the bottom line everyone thinks the goal of pH control is better extract. That isn't the only goal. Better tasting beer is. It is recognized that the pH's goals stated in the literature represent a compromise as we haven't much choice but it's also recognized that best extract yield isn't the only thing coupled to profits. Beer quality has something to do with it.

Setting your boil start pH is what makes your beer taste great.

 

[ajdelange]

Enzyme action occurs at the same rate until you get above pH ~6.5 at mash temperature.

To be honest, I interpreted his pH 6.5 comment as referring to the pH above which amylase activity falls off significantly, which would be roughly consistent with the pH profiles of these enzymes. But perhaps I missed something?

Yes.

That makes it pretty clear to me that he thinks all the enzymes, not only the amylases, have this property. Still agree with him?

 

[ajdelange]

Setting your boil start pH is what makes your beer taste great.

Can you explain why this is so (sans vitriol)?

 

[hopjuice_71]

Think about what you are saying. There are enzymes that exhibit broad activity peaks of course. Apparently papain is flat over entire range of biological possibility. But hotdog's statement was that enzyme activity is constant until pH 6.5 is reached. How about pH 4. That's below 6.5. Is the activity of alpha amylase the same at 4 as it is at 6? And how about beta amylase? The guys that sell it say its range of peak activity is 4 - 5.5. Is it's activity at 5 the same at 5 as it is at 6.5. And how about beta glucanase. The Enzyme Education Institute says its maximum activity occurs between 3.5 - 6. Is it's activity at 6.5 the same as 5? And what about the myriad of other enzymes in barley malts that catalyze the reactions that produce the flavor aroma and body characteristics we seek? Are their activities flat over the range of possible mash pHs? Clearly no or mashing in a certain range would not result in better tasting beers.

Perhaps because of commercial brewing practices where a 2% yield in extract may have significant impact on the bottom line everyone thinks the goal of pH control is better extract. That isn't the only goal. Better tasting beer is. It is recognized that the pH's goals stated in the literature represent a compromise as we haven't much choice but it's also recognized that best extract yield isn't the only thing coupled to profits. Beer quality has something to do with it.

Please note that I am not debating the impact of pH on beer quality. I just don't have the background or experience to do so. I will most definitely defer to and trust your expertise and experience until I have evidence to think otherwise.

I do, however, know polysaccharide/carbohydrate processing enzymes.. ..most likely better than anyone here would care to know and I do have some thoughts on the issues of pH optima and reporting them - I am not trying to defend or anger anyone here. Yes, you will see ranges of pH activity on commercial products and reported in textbooks or review articles. These are typically very conservative. Several of my enzymes are commercially available and the distributor reports much tighter parameters for usage than is necessary. To find the real information one has to look at and interpret the primary literature. With respect to brewing, I am right now looking an article published out of the Carlsberg Laboratories on the four isozymes of barley beta-amylase (Carlsberg Res. Common, vol. 52, p. 313-326, 1987). All four isozymes show >~80% activity over a pH range between 4 and nearly 7.5. For alpha amylase I am looking at pH profile that has >~80% activity over a pH range between 4 and 6.5 (J. Inst. Brewing, vol 80, p. 181-187, 1973). Clearly, with respect to pH, these enzymes are more forgiving than we are typically led to believe. I don't have time to specifically look up the barley glucanases, etc., but having worked on equivalents from other sources I am certain their pH tolerances are reported equally conservatively. So, I have no doubts that a mash would convert quite readily at pH 4 or 6.5. I make NO claims, however, that the beer would be good. I'm too much of a chicken to try it and experimenting with my brewing hobby is just a little to close to my day job.. ..

 

[sixhotdogneck]

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. That start of boil pH is what helps controls protein coagulation and precipitation, hop utilization (taste) and yeast control, all which have a much more prevalent effect on the final product.

 

[hopjuice_71]

That makes it pretty clear to me that he thinks all the enzymes, not only the amylases, have this property. Still agree with him?

Oops, sorry, didn't see this. Please see immediately above.

 

[cire]

How important is adjusting for pH?

In early brewing I didn't know the importance of pH yet knew my beers needed improvement. Later, maybe thirty years since, suitable pH strips were hard to source and were quite expensive, while electronic meters were out of the question for an amateur. Having learned how to treat water and the options there were, I would mash in with hope and expectation of no necessary adjustment and mostly there wasn't. Mash pH is measured when there is nothing more important needed. With my system it is can be more important to measure sparge pH to know when to stop, while anyone mashing full volume with the same recipe getting the same mash pH would not face that task and also produce a beer different to mine.

When one of the first electronic pH meters was demonstrated at a Whitbread brewery, it found that brewery's mash pH to be consistent at around 5.4. Just as then, nearly 100 years ago, if you brew correctly, mash pH will be correct. Even with infinite potential combinations of grains, water and minerals, there are but finite numbers of acceptable combinations to produce an acceptable mash pH and fewer when restricting water sources and mineral content. Certainly there is a difference in wort composition depending upon mash pH, but whether taste is the best arbiter I don't know. I think a good beer mashed at pH 5.5 would still be a good beer if mashed at pH 5.2 and any difference in taste would be thought better by some and not as good by others. Personally I prefer my silky smooth and warming stouts to be mashed at the lower end of the scale compared to that which are so often touted here.

Much advice is given with the best of intentions, but it is often given or taken in the wrong context. Many of us sit in our own little world with our precious pints to maybe assume what little or lot we know fits all and sundry and what suits us has universal application. Charlie Bamforth was mentioned earlier, maybe some of his more cautious words might be worth another read.

 

[ScrewyBrewer]

It is important enough to know the parameters and get in the ballpark. Not important enough to lose sleep over. I'm way more concerned with yeast health, sanitation, cold side oxidation, water mineral profile, ingredient quality and good old recipe formulation. Cheers.

I'm just as interested in the entire brewing process as anyone. From ingredient selection to carbonation level. I like brewing a lot and enjoy the entire process. But the challenge of getting everything right from OG to FG and everything in between is a goal of every batch I brew.

To me predicting mash pH is a bit like gambling which I never do. It's both a goal and a challenge. But I like to know how a mash pH is influenced by the grains in any given recipe. Do I expect everyone to find brewing water properties and mash pH as exciting as I do? Of course not. In fact, the percentage of brewers that I know who do is less than 1% at best. In the end its all a matter of personal preference.

I've brewed with people who fill their kettles with water from a 100 foot long hose. In the heat of the Summer sun it reeked so bad of vinyl plastic I wouldn't give it to a pet to drink. And yet they love their beer.

As I sip a delicious Kolschbier whose keg is about to be kicked as I type this.

 

[rhys333]

I selected "I take pH readings because it will make my beer better".

There's a bit more to it though. I've been taking readings for a while now and I know how accurate a predication I can get from brewing software in relation to my system. On that basis, I could in theory skip the pH readings and still get within about 0.05 pH. I still need to know how pH impacts my beer though.

 

[ScrewyBrewer]

I selected "I take pH readings because it will make my beer better".

There's a bit more to it though. I've been taking readings for a while now and I know how accurate a predication I can get from brewing software in relation to my system. On that basis, I could in theory skip the pH readings and still get within about 0.05 pH. I still need to know how pH impacts my beer though.

I selected the same as you. When rebrewing the same recipe a few times and seeing similar pH readings the challenge is pretty much gone. Unless I'm still trying to get the predicted and actual pH readings closer.

 

[ScrewyBrewer]

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. That start of boil pH is what helps controls protein coagulation and precipitation, hop utilization (taste) and yeast control, all which have a much more prevalent effect on the final product.

...and the right pH for it all starts in the mash, correct? I'm trying to understand what you're getting at. Is it you don't think mash pH needs to be constrained to a range of 5.2 to 5.6 at all?

 

[Silver_Is_Money]

I've brewed with people who fill their kettles with water from a 100 foot long hose. In the heat of the Summer sun it reeked so bad of vinyl plastic I wouldn't give it to a pet to drink. And yet they love their beer.

That's not only disgusting, it's downright unhealthy. Vinyl chloride can cause cancer.
https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/vinyl-chloride

 

[ScrewyBrewer]

That makes it pretty clear to me that he thinks all the enzymes, not only the amylases, have this property. Still agree with him?

The question of temperature should be part of the equation too. Since enzymes are denatured during the mash at varying temperatures. How does temperature influence the 4 to 6.5 pH range mentioned.

 

[hopjuice_71]

The question of temperature should be part of the equation too. Since enzymes are denatured during the mash at varying temperatures. How does temperature influence the 4 to 6.5 pH range mentioned.

Good point. pH does influence protein stability and this may be further influenced in combination by temperature, and vice versa. However, the data I have seen on conversion at mash temperatures vs pH seem to roughly parallel those of the pH profiles, which have been done at a variety of temperatures ranging from RT to mash temps, depending on the study. Honestly, though, this is not a super exhaustive analysis.

 

[hopjuice_71]

...and the right pH for it all starts in the mash, correct? I'm trying to understand what you're getting at. Is it you don't think mash pH needs to be constrained to a range of 5.2 to 5.6 at all?

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 and in and of itself is not key to determining beer flavors other than b) determining the starting kettle pH; however, c) the kettle pH could be corrected after an “unusual” mash pH to provide an appropriate pH pipeline to positive final beer properties. Hopefully I have that right. I’ve spent the last couple of days scouring the literature about various brewing and pH studies (when I should have been doing my real work…). 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! 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? 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.


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….).

 

[ScrewyBrewer]

Much advice is given with the best of intentions, but it is often given or taken in the wrong context. Many of us sit in our own little world with our precious pints to maybe assume what little or lot we know fits all and sundry and what suits us has universal application. Charlie Bamforth was mentioned earlier, maybe some of his more cautious words might be worth another read.

@cire thank you for sharing these with us. Finishing the first pass at reading 'pH in Brewing: An Overview' I came away with a new perspective and understanding of pH in brewing beer. I can see where this was used as a basis for a lot of pH information published for homebrewing. Sadly though I feel a lot of the details were lost in the translation. When the information from a technical paper was diluted down into a magazine format easier to read by most. I've bookmarked the articles for future reference and enjoyment.

"There is a consensus that pH has a direct bearing on flavor stability, foam stability and colloidal stability, yet no fully documented rationale for these effects. Much remains to be researched in the world of pH and brewing." ~Charles W. Bamforth

 

[Tribe Fan]

I took might make my beer better because after reading all this stuff, and I've read most of it, who knows if what I measure is actually what it is. But at least its another data point for a good or bad batch.

The fact that my enzymes are all named Kenny though, opens a door I would have not otherwise went through.

 

[Silver_Is_Money]

@cire thank you for sharing these with us.

Indeed! Great links. It appears that both the year 1974 and the year 2000 documents emphasize that much is still unknown about beer brewing science. I did learn that per D.G. Taylor a mash that comes in at a pH of 5.51 when 50 ppm of Ca++ is present will drop to pH 5.10 if Ca++ is bumped up to 350 ppm. At a buffer value of 35 my MME version 4.00 spreadsheet matches this pH shift exactly. So I suspect that D.G. Taylor is perhaps merely regurgitating Kolbach here. I wonder if he actually was able to 100% verify this with testing? I believe that A.J deLange may suggest that the pH shift effect due to mineral additions is not actually this pronounced.

Also interesting was that W. Kunze suggests that a mash at between 5.5 and 5.6 pH is optimum with respect to attenuation limit, protein breakdown, viscosity, lautering rate and restriction of color increase, but no mention here is made with respect to flavor. As I'm shifting to a belief that this is the ideal mash pH range, it was good to hear a true master thinking this way.

 

[sixhotdogneck]

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 and in and of itself is not key to determining beer flavors other than b) determining the starting kettle pH; however, c) the kettle pH could be corrected after an “unusual” mash pH to provide an appropriate pH pipeline to positive final beer properties. Hopefully I have that right. I’ve spent the last couple of days scouring the literature about various brewing and pH studies (when I should have been doing my real work…). 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! 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? 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.


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….).

Yes, you are correct, thank you for the clarity and summarization.

 

[GnenieGone]

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….).

Thanks for doing that work. Saved me the hastle. Sounds like you found a new line of study! [emoji16]

Anyone who has time and money can do a subjective design of experiment. Brew an exact recipe over and over changing and recording pH along the life of a beer from mash to undrinkabilty...which could be years. But since pH can be adjusted with multiple chemicals, that would have to be accounted for. Also what's the effect of pH on different styles? I think finished sours are low 3ish to keep from bacteria growing over the years of storage but what about an IPA? IDK. It's quit an undertaking.

Hence I just go with Brew'n Water and base RO water then aim for 5.3 to 5.5 depending on style. It might be uninteresting to do the same thing pH/chemical wise, but after 200 HBs playing around with recipes is the fun part anyway.