Water Chemistry Calculator pH Discrepancy

[Silver_Is_Money]

You can call it whatever you want to call it, but perhaps you should re-evaluate throwing stones, especially since we are all perched rather precariously in water and pH estimation glass houses.

Your sheet is firmly planted in the camp using a color based acidity proxy and the much touted “log base 10” solution doesn’t do anything a weighted average of the calculated DI pH values doesn’t already do. So evidently you found a more difficult way of finding a weighted average?

Does that make your sheet any less interesting? I don’t think so, but it sure isn’t groundbreaking or at all special. It is what it is so to speak.

You’ll never have the users Brun Water does (neither will I or anyone else for that matter) and sniping Martin at every chance you get won’t change that.

For clarity, the base 10 logs method utilized by MME determines how a given weight of grist at one DI pH will interact with a give weight of grist at another DI pH. There is no need to ascertain malt acidity, as it is presumed by MME to be fully inherent within the malts DI pH. pH = minus log(H+), where H+ is the effective molar concentration of hydronium ions. If a malt achieves a real world measured DI pH, it does so factually because a highly specific and quantifiable molar concentration of hydronium ions have been liberated by it into the DI water during the mash. Buffering as such only becomes a concern with regard to how acids or bases or minerals added to shift the inherent pH of the aggregate grist interact to achieve a targeted mash pH.

I'm fully aware that the incredibly simplistic presumptions behind this log based method are open to the potential of being incorrect at a multiplicity of levels, and I have fully welcomed A.J.'s rather rigorous attacks upon it. But as comparisons of actual real world mash pH's measured by forum members continue to pile in and weigh favorably toward it, and seem to at the same time drift far from A.J.'s generally much higher calculations of predicted mash pH, this real world of comparisons of actual mash pH measurement vs. software math model prediction of mash pH will prove to be the ultimate proving ground of validity.

The logs on the other hand do not involve themselves at all in any sort of weighted average determination of DI pH values for malts and unmalted grains. I have primarily relied heavily upon Briess data (which they provided to me upon request) for the most part in that regard. I will grant that DI pH values are likely to be one of the weakest links in any software solution for mash pH, and I fully admit that if my software (or any other software playing in this arena) had access to reliable DI pH values for all malts across the entire spectrum of malts/grains, the picture of reliable mash pH prediction would be brighter and more clear.

I'll admit that I may be all wet in my log based approach, but at least I'm open to telling everyone up front how it works (and I have already done so on this forum), and that it is fully functional and free. And I'm open to the embarrassment of being wrong. If proven wrong via "valid" real world mash pH measurements as they come in and accumulate, and presuming that they weigh against MME predictions, I'll learn from it, admit it, and either modify my approach or fold and accept the approach of another.

As opposed to an outlook that teaches us to "judge not lest you be judged" and thereby have your fragile glass house shattered, my Objectivist philosophical outlook teaches me to judge and be prepared to likewise be judged. If we do not meticulously judge both our work and the work of others against a world of "valid" real mash pH measurements by the community of homebrewers, how can we ever expect to come to any semblance of truth in regard to mash pH prediction? Mash pH softwares reliability and value at prediction is not to be determined via a popularity contest, just as any other science is not settled by popularity of mere opinion. Science is a measurement vs. validity of prediction contest. I understand fully that I stand no chance of winning a popularity contest, but there is no relevant value to be placed in my doing so.

 

[Big Monk]

Well, to further muddy the waters, I get the following when using the charge method:

Grist pH (just malt w/ "American 2-Row" selected) - 5.65

Grist + Minerals pH - 5.57

Grist + Minerals + Lactic Acid pH - 5.50

Note that I am assuming 5.75 for American 2-Row. Obvious shift DI pH up or down depending on maltster, lot, etc. will change this. For various other values:

Grist + Minerals + Lactic Acid pH (DI pH ovveride for A2R set to 5.50) - 5.28

Grist + Minerals + Lactic Acid pH (DI pH ovveride for A2R set to 5.65) - 5.41

Grist + Minerals + Lactic Acid pH (DI pH ovveride for A2R set to 5.72 (think MpH)) - 5.47

Grist + Minerals + Lactic Acid pH (DI pH ovveride for A2R set to 5.90 (think MpH)) - 5.63

 

[Silver_Is_Money]

Even if and when we come to the point of reasonably understanding the nominal DI pH for every average grist component, we will never know if any given real world lot of malt or unmalted grain picked up by the homebrewer at his/her LHBS complies highly with the presumed nominal DI pH for same. There is always a percentage of likelihood that it will not.

 

[Big Monk]

For clarity, the base 10 logs method utilized by MME determines how a given weight of grist at one DI pH will interact with a give weight of grist at another DI pH. There is no need to ascertain malt acidity, as it is presumed by MME to be fully inherent within the malts DI pH.

My point was that you ask the user for color. If the user changes the color of the malt, the DI pH (Pre Alk, Ca, Mg) changes. So somewhere, I'm not sure where or how, your sheet is the same old hat as BW, Kai, MpH, etc., i.e. using color to predict acidity in some way shape or form.

Obviously you are getting better results because you account for DI pH of the individual grains. That's something that I started doing years ago in BW to try and match better the real world numbers myself and my brewing buddy were seeing.

For clarity, the base 10 logs method utilized by MME determines how a given weight of grist at one DI pH will interact with a give weight of grist at another DI pH.

The logs on the other hand do not involve themselves at all in any sort of weighted average determination of DI pH values for malts and unmalted grains.

Right. My other point here was that you are hanging your hat on a method that is duplicated exactly by calculating the weighted contribution of the DI pH values. I don't know what you are running behind the scenes but I can tell you that calculating the weighted contribution of the Di pH values (Post Alk, Ca, Mg) gives the exact same value for Pre Acid/Base Addition pH.

I appreciate the work you are putting into this. I think we all do. I also think we could do without your negative opinions on the other options. Present the case as to why MME may work better and move on. It does a disservice to your hard work when you slag someone else's. We have the luxury of making changes on the fly and getting them out to the 2 users who may be using our stuff regularly. In fact, since the explosion of ideas that was August 2018, your sheet has gone from v.1.60 to v.5.10.

It's not that easy for someone like Martin to roll out those kind of rapid changes and I would expect him to want more data than a handful of casual water software users on this forum, who have favorable results based on a single batch with our software, to sway him in that direction.

 

[ScrewyBrewer]

Mash pH prediction using color based or DIpH based formulas are subject to similar amounts of unpredictability. And for very different reasons. In a large-scale brewing situation, I would favor titration testing each batch of grain used in any given recipe. In the real world homebrewer situation, I don't see that happening. Except for the small minority of homebrewers who have the time equipment and passion needed to test and then brew every batch. Taking a poll of 33 MCHA members including myself only 2 members owned and used a pH meter in their brewing. Add to that another 4 or 5 who admitted to tossing in a pinch of gypsum here and there at times.

Color is a different story. Every homebrewer doing all grain brewing is aware of grain color. Maybe not much focus is given to whether the grains are from Briess, Dingmans, Simpsons, GoldSwaen, Avangard, etc. All of which are known to produce similar color grains with varying DIpH values. Neither approach is 'perfect' but I see a color based approach as being a more mainstream approach for homebrewing for the reasons I've described.

 

[mopowers]

Damn, I didn't realize this is such a complicated topic. I ended up brewing my pale ale yesterday and tossed in 1.2 ml of lactic acid in the strike water. Without knowing what the actual pH was, I hope it turns out. The OG was 1.062, so it should be a good'n.

 

[mopowers]

Which mash pH predictor calculator do you guys think is most accurate?

 

[Silver_Is_Money]

Which mash pH predictor calculator do you guys think is most accurate?

I must emphasize yet again that it's not a popularity contest. Thinking devoid of testing and verification essentially equates to mere opinion, and mere opinion is generally on par with nothing more substantial than whim and wishes. We need those with pH meters to carefully and meticulously test our mash pH software across a broad range of recipes spanning broad spectrums of SRM/ECB batch colors, mash thicknesses, percentages of deep roast and crystal malts, mineralization levels, etc... And I would ask that mash pH samples be taken no sooner than 30 minutes into the mash, and that carefully and quite recently calibrated pH meters be allowed to sit untouched in actual room temperature samples (not merely presumed to be equivalent to room temperature due to being ATC compensated) for several minutes with no stirring to achieve stability.

 

[Big Monk]

Which mash pH predictor calculator do you guys think is most accurate?

I wouldn't trust any currently available or future releases of any of them for "flying blind", i.e. not taking pH measurements.

We would like a pH meter to be a validation tool (confirming spreadsheet predictions) but it is often a troubleshooting tool (figuring out why estimation and reality don't jive).

 

[Silver_Is_Money]

No level of "confirmation bias" must ever be permitted to creep into anyone's pH readings either.

https://en.wikipedia.org/wiki/Confirmation_bias

http://laboratory-manager.advanceweb.com/confirmation-bias/

And failures must be reported as frequently as successes. I suspect that success stories get reported (or outright fabricated) far more frequently than failures.

Personally, I am biased. But at least I'm honest about it.

 

[ScrewyBrewer]

I wouldn't trust any currently available or future releases of any of them for "flying blind", i.e. not taking pH measurements.

We would like a pH meter to be a validation tool (confirming spreadsheet predictions) but it is often a troubleshooting tool (figuring out why estimation and reality don't jive).

That’s fair a pH meter can and should be used for both.

 

[ScrewyBrewer]

I brew for the same reasons I chase mash pH. I love the challenge. And the satisfaction I get from both. Every brewday is a learning experience. Whether fine tuning an old favorite or proving out a new recipe.

 

[dmr]

It is indeed the case.
No one really knows how this program works and the author isn't talking. From his frequent contributions to this forum we can sort of deduce that its algorithm is based mostly on empirical methods based on the experiences of people who use his program. Earlier this year people here reported that they were finding that increasing the DI water to grist ratio caused it to predict lower pH. This clearly cannot happen. The author reported that fixed. Another reader here found with it that equivalent amounts of two different basic salts caused it to estimate different pH shifts. Clearly this is wrong. Several people have, as you did, reported pH predictions, especially with dark malts, that are much lower than makes sense. Author's response to this is that he needs to get more reports on dark beer mash pH from his users in order to be able to fix this. All of these solidify the impression that the algorithm is empirical rather than based on the chemistry. The general problem with empirical solutions is that they tend to be valid only under certain conditions - those under which the data underlying them were gathered. When those conditions aren't met, the creator often tries to patch the algorithm to "fix" the problem by "tweaking" it to incorporate the outliers. Often this causes another problem to pop up. I think that's what happening here.

Indeed, the algorithm is empirical. The equations utilized in the algorithm are largely based on equations that can be found in Kai Troester's 2009 paper The effect of brewing water and grist composition on the pH of the mash. These equations are extensively discussed in the two papers A Homebrewing Perspective on Mash pH I and A Homebrewing Perspective on Mash pH II, both which can be found at homebrewingphysics.blogspot.com.

 

[ajdelange]

Kai's work gives us fits to measurements he took which allow us to estimate malt parameters from color. But when he uses those estimates in his spreadsheet he uses them consistent with the chemistry. Thus the malt data is empirical (as it has to be in any estimation process where the actual malts being used are not measured) but the use of that data is analytical as the laws of chemistry are invoked to calculate a pH. Kai's spreadsheet would not tell you that adding more water to a mash will cause a drop in mash pH (unless the water has been acidified).

Bru'n water states plainly that it uses Kai's work for the malts but apparently uses the malt parameters deduced from his models in some non analytical fashion as it will (or has in the past) estimated lower mash pH when more water is added. That violates the laws of chemistry.

 

[dmr]

Kai's work gives us fits to measurements he took which allow us to estimate malt parameters from color. But when he uses those estimates in his spreadsheet he uses them consistent with the chemistry. Thus the malt data is empirical (as it has to be in any estimation process where the actual malts being used are not measured) but the use of that data is analytical as the laws of chemistry are invoked to calculate a pH. Kai's spreadsheet would not tell you that adding more water to a mash will cause a drop in mash pH (unless the water has been acidified).

Bru'n water states plainly that it uses Kai's work for the malts but apparently uses the malt parameters deduced from his models in some non analytical fashion as it will (or has in the past) estimated lower mash pH when more water is added. That violates the laws of chemistry.

The following is my understanding of BrunWater's (BW's) calculations of distilled-water mash pH. BrunWater (in essence) calculates distilled-water pH using

pH = 5.75 - (0.17/R) Sum_i (f_i * A_i),

where R is the mash thickness (liters / kg), f_i is the fraction of malt i in the mash, and A_i (mEq/kg) is the acidity of malt i (with respect to a fiducial pH of 5.75). FWIW (not much), dimensional analysis readily tells us the units of the factor 0.17 are liter/mEq.

This dependence upon mash thickness R is readily apparent in this equation. It's presence gives the well-know feature of BW that smaller values of R predict values of mash pH that are further away from 5.75 (changed to 5.76 in the latest version of BW).

I do not believe that Kai Troester (KT) is entirely innocent in this. The last equation in Sec. 3.4 and first equation in Sec. 3.5 of KT's 2009 paper ("The effect of brewing water...") are (in essence) of the form of the above equation used by BW. The logical conclusion is that the author of BW was lead (or mislead) to adopt these equations of KT in BW.

KT later recognized that the above equation is not correct: the first equation in KT's 2012 paper "Beer color to mash pH" replaces the factor (0.17/R) by 1/B, where KT correctly points out that B is the buffering capacity of the malt. This correction is reflected in KT's spreadsheet (and his website Brewer's Friend), which do not exhibit a shift of distilled-water pH with mash thickness.

Cheers!

 

[ScrewyBrewer]

I do not believe that Kai Troester (KT) is entirely innocent in this. The last equation in Sec. 3.4 and first equation in Sec. 3.5 of KT's 2009 paper ("The effect of brewing water...") are (in essence) of the form of the above equation used by BW. The logical conclusion is that the author of BW was lead (or mislead) to adopt these equations of KT in BW. I now understand why your

KT later recognized that the above equation is not correct: the first equation in KT's 2012 paper "Beer color to mash pH" replaces the factor (0.17/R) by 1/B, where KT correctly points out that B is the buffering capacity of the malt. This correction is reflected in KT's spreadsheet (and his website Brewer's Friend), which do not exhibit a shift of distilled-water pH with mash thickness.

Cheers!

@dmr thank you for clarifying the discrepancies in KT's 2009 and then later revised 2012 formulas regarding mash thickness and buffering. I have been using your MpH Water Calculators v2.0 and v3.0 for a few years now. I always wondered why the MpH mash pH predictions, with salts and acids added, differed by ~.07 pH when compared to BW.

 

[Silver_Is_Money]

@dmr thank you for clarifying the discrepancies in KT's 2009 and then later revised 2012 formulas regarding mash thickness and buffering. I have been using your MpH Water Calculators v2.0 and v3.0 for a few years now. I always wondered why the MpH mash pH predictions, with salts and acids added, differed by ~.07 pH when compared to BW.

Beware that before revealing this error correction an explicit statement to the effect that this is all based upon merely empirical grounds in the first place was professed. That said, and given this profound error correcting revelation, BW has been gifted with the evolutionary opportunity (if it so chooses) to effectively transition itself from a geocentric view of the universe to a heleocentric view replete with epicycles.

Unless of course, the corrective replacement of 0.17/R by 1/B removes from the formulative structure of mash pH prediction all levels of empiricism.

 

[Big Monk]

Beware that before revealing this error correction an explicit statement to the effect that this is all based upon merely empirical grounds in the first place was professed. That said, and given this profound error correcting revelation, BW has been gifted with the evolutionary opportunity (if it so chooses) to effectively transition itself from a geocentric view of the universe to a heleocentric view replete with epicycles.

Unless of course, the corrective replacement of 0.17/R by 1/B removes from the formulative structure of mash pH prediction all levels of empiricism.

In order to spare those allergic to word salad, here is a translation:

Before this post, A.J. said earlier that Brun Water is empirically based. Given this info, this would be a good opportunity for Martin to evaluate and apply this correction.

 

[ScrewyBrewer]

Beware that before revealing this error correction an explicit statement to the effect that this is all based upon merely empirical grounds in the first place was professed. That said, and given this profound error correcting revelation, BW has been gifted with the evolutionary opportunity (if it so chooses) to effectively transition itself from a geocentric view of the universe to a heleocentric view replete with epicycles.

Unless of course, the corrective replacement of 0.17/R by 1/B removes from the formulative structure of mash pH prediction all levels of empiricism.

Agreed. @dmr has provided us with a solid foundation for mash pH prediction based solely on the laws of chemistry. Over time the recording of actual mash pH measurements against mash pH predictions will be the real test. Can pH predictions based on empirical data ever be more accurate than predictions based on the laws of chemistry?

 

[mabrungard]

Agreed. Can pH predictions based on empirical data ever be more accurate than predictions based on the laws of chemistry?

Yes indeed they can when the full understanding and/or application of the chemistry is not incorporated.

In other words, if you've got a great and factual calculation for a part of the chemical reaction and haven't accounted for other aspects of that reaction, then you are no better off than an empirical estimate.

 

[Big Monk]

In other words, if you've got a great and factual calculation for a part of the chemical reaction and haven't accounted for other aspects of that reaction, then you are no better off than an empirical estimate.

This works in multiple ways though. Empirical results are extremely useful for a broad number of users if there is agreement between those results and all users. However, empirical results that differ between users can only be applied with confidence to that specific user's brewhouse, i.e. if my empirical results don't match yours, they may only be valid for my brewery.

Trying to establish the base calculations based solely on charge conservation and the known chemistry is a good step forward for "leveling" the field but introduces things like titration characteristics for malt that just may not be practically estimated, functions in Excel that make it hard for some users to even use the code, etc.

There are tradeoffs in both directions. I'm personally trying to come up with a user friendly application of the charge conservation method with decent estimates for titration characteristics. It's slow going.

 

[ScrewyBrewer]

There are tradeoffs in both directions. I'm personally trying to come up with a user friendly application of the charge conservation method with decent estimates for titration characteristics. It's slow going.

Unless I've completely misunderstood, either of the two approaches provides an end user with similar benefits, limitations, and tradeoffs. The analytical methodology relying solely on charge conservation and chemistry may be best suited for use under near-laboratory conditions. Let me explain. I say this because very few brewers have the resources needed to titration test every grain type used in their recipes prior to brewing them. I would venture a guess those that do often come within an acceptable range of mash pH prediction. And their brewing notes record the actual and predicted mash pH measurements to use as a reference when brewing that recipe again.

The empirical methodology differs by bending the mash pH prediction curve based on known outcomes of prior predictions and actual mash pH measurements. Again I would guess for most brewers the actual mash pH comes within an acceptable range of mash pH prediction. And users record the actual and predicted mash pH measurements in their notes to refer to when brewing that recipe the next time. I doubt anyone thinks either of the two approaches is foolproof. On one hand, we have a tool that relies on input based on accurate titration testing and buffering. On the other one relying on grain color, mash thickness, and empirical or anecdotal evidence.

 

[Big Monk]

Unless I've completely misunderstood, either of the two approaches provides an end user with similar benefits, limitations, and tradeoffs. The analytical methodology relying solely on charge conservation and chemistry may be best suited for use under near-laboratory conditions. Let me explain. I say this because very few brewers have the resources needed to titration test every grain type used in their recipes prior to brewing them. I would venture a guess those that do often come within an acceptable range of mash pH prediction. And their brewing notes record the actual and predicted mash pH measurements to use as a reference when brewing that recipe again.

The empirical methodology differs by bending the mash pH prediction curve based on known outcomes of prior predictions and actual mash pH measurements. Again I would guess for most brewers the actual mash pH comes within an acceptable range of mash pH prediction. And users record the actual and predicted mash pH measurements in their notes to refer to when brewing that recipe the next time. I doubt anyone thinks either of the two approaches is foolproof. On one hand, we have a tool that relies on input based on accurate titration testing and buffering. On the other one relying on grain color, mash thickness, and empirical or anecdotal evidence.

I agree with you, however, if even an educated guess at DI pH and at least the first titration constant is a better fit than a color proxy, the rest of the charge conservation method (acids, minerals, water, etc.) is bulletproof.

I am having more issues with getting everything in a user friendly form for folks (solver doesn’t work for everyone and macros and other things aren’t always supported in all versions of Excel) than coming up with decent input data for pH and titration constants.

 

[ScrewyBrewer]

I agree with you, however, if even an educated guess at DI pH and at least the first titration constant is a better fit than a color proxy, the rest of the charge conservation method (acids, minerals, water, etc.) is bulletproof.

I won't argue that point with you. In fact my first attempt at water calculations relied on grain DIph entries for input. At the time only myself and another member of our club took the time to do any test mashes. So for the next two years my focus shifted to color based predications. But I never really shut the door on adopting DIpH based predictions.

I am having more issues with getting everything in a user friendly form for folks (solver doesn’t work for everyone and macros and other things aren’t always supported in all versions of Excel) than coming up with decent input data for pH and titration constants.

Excel supports VBA/macro coding on all platforms but other non-Excel spreadsheets do not.

 

[ajdelange]

Again the community seems to miss the essential point that there are two parts to getting better pH predictions.
I. Having a model that correctly reflects the chemistry
II. Putting good data into it.

Both parts are necessary. Putting lousy data into a good model leads to the old GIGO (Garbage In - Garbage Out) expression that used to kick around the engineering community a few years back. It doesn't matter whether you have the best model in the world. Feeding it bad data will result in a poor result. But the benefits of a good model are clear. Putting the best malt data into a program that thinks dilution has an effect on mash pH isn't going to give very good predictions and the problem now becomes one of getting good malt data, Even if we don't have good malt data an accurate model allows us to derive correct answers to questions like "Suppose I have a malt with these characteristics. How is the pH effected if I use 30% more mash water?" (Answer: if the alkalinity is accounted for separately it isn't).

Can pH predictions based on empirical data ever be more accurate than predictions based on the laws of chemistry?

Yes indeed they can when the full understanding and/or application of the chemistry is not incorporated.

If parts of the applicable chemistry are omitted, ignored or misunderstood then we can't say that the prediction is based on laws the chemistry. This does not mean that we simplify where the effect is so small as to be unnoticeable or insignificant (e.g. Debye Hückle).

In other words, if you've got a great and factual calculation for a part of the chemical reaction and haven't accounted for other aspects of that reaction, then you are no better off than an empirical estimate.

In other words you are saying that an empirical approach can better than an incorrect analytical one. This is about as useful as saying that the bear defecates in the woods. But, of course, I am not suggesting that anyone develop his own laws of chemistry but rather that they should use the laws of chemistry that are known. I recognize that there are some here that are still struggling to understand this chemistry to the point that they can correctly implement it in their spreadsheets/calculators. But it is out there and if they keep at it they will get there eventually.

Now I am most curious as to the phrase "if you've got a great and factual calculation for a part of the chemical reaction and haven't accounted for other aspects of that reaction" and would appreciate some clarification on that with an example if possible.

 

[ScrewyBrewer]

I agree with you, however, if even an educated guess at DI pH and at least the first titration constant is a better fit than a color proxy, the rest of the charge conservation method (acids, minerals, water, etc.) is bulletproof.

I've been working on ezRecipe v2.01 a lot lately. A new feature adds a way to override the Gen I color based DIpH prediction with any of the known DIpH grain values. I believe what I've done is make ezRecipe v2.01 Gen II compliant. The upcoming version ezRecipe builds on the elegant formulas provided by @dmr in his current MpH v3.0 brewing water spreadsheet. Regression testing the new features against Brewers Friend is ongoing and so far the results are matching up nicely. Now all we need is a database of reliable DIpH values for our most popular maltsters by their grain types to feed in.

 

[Big Monk]

I've been working on ezRecipe v2.01 a lot lately. A new feature adds a way to override the Gen I color based DIpH prediction with any of the known DIpH grain values. I believe what I've done is make ezRecipe v2.01 Gen II compliant. The upcoming version ezRecipe builds on the elegant formulas provided by @dmr in his current MpH v3.0 brewing water spreadsheet. Regression testing the new features against Brewers Friend is ongoing and so far the results are matching up nicely. Now all we need is a database of reliable DIpH values for our most popular maltsters by their grain types to feed in.

I’d argue you haven’t. I don’t mean any offense by that either. I started using a DI pH override 3 years ago and it dramatically increased the accuracy of predictions.

I’d have to know the nuts and bolts of what you did but unless you’ve supplanted color based acidity proxies, you have merely increased the accuracy of those color based estimations by shoring up the DI pH portion of the calculations.

With that said, DI pH values will dramatically increase even color based estimations. The fact of the matter, however, is that DI pH is only a portion of the q calculation for malt.

Mr. Riffe’s calculator is still very much rooted in color based estimation. I’m looking forward to seeing what he plans on issuing in the coming months.

 

[ScrewyBrewer]

I’d argue you haven’t. I don’t mean any offense by that either. I started using a DI pH override 3 years ago and it dramatically increased the accuracy of predictions.

I’d have to know the nuts and bolts of what you did but unless you’ve supplanted color based acidity proxies, you have merely increased the accuracy of those color based estimations by shoring up the DI pH portion of the calculations.

With that said, DI pH values will dramatically increase even color based estimations. The fact of the matter, however, is that DI pH is only a portion of the q calculation for malt.

Mr. Riffe’s calculator is still very much rooted in color based estimation. I’m looking forward to seeing what he plans on issuing in the coming months.

@RPIScotty I guess I've lost track of the Gen II specification over the last several months. What are they again? I thought the Gen II specification was to move away from Gen I color based predictions and instead move to individual grain DIpH based predictions. If this is the case then ezRecipe is Gen II compliant or will be once I release this latest version currently under testing.

The ezRecipe v2.01 mash pH and water property results closely match those in Brewer's Friend when using the DIpH override feature. When the DIpH value of grain is entered ezRecipe overrides all color based mash pH predictions used in Mark's MpH v3.0 spreadsheet but still uses Mark's water property calculations. You'll be able to get a better understanding of my approach in the coming weeks.

 

[Big Monk]

@RPIScotty I guess I've lost track of the Gen II specification over the last several months. What are they again? I thought the Gen II specification was to move away from Gen I color based predictions and instead move to individual grain DIpH based predictions. If this is the case then ezRecipe is Gen II compliant or will be once I release this latest version currently under testing.

The ezRecipe v2.01 mash pH and water property results closely match those in Brewer's Friend when using the DIpH override feature. When the DIpH value of grain is entered ezRecipe overrides all color based mash pH predictions used in Mark's MpH v3.0 spreadsheet but still uses Mark's water property calculations. You'll be able to get a better understanding of my approach in the coming weeks.

If you don't use color, how do you get the acidity of the grain?

Riffe's spreadsheet calculates the Grist pH by using an assumed DI pH (or in the case of the savvy, a weighted user input that sums all the DI pH values for at the very least the base malts) and the grist acidity, which comes from color and the grist fraction of each malt.

If you eliminate the latter, the Grist pH will just be the combined DI pH of the grist, which doesn't say much about how the malt will affect the Grist pH.

I hate attaching names and labels to things (I despise the LODO moniker) because it makes things seems a bit pretentious, but Gen II, as far as I've ever known, is the replacement of the color based proxy for acidity for the actual q value (mEq) of the grain bill based around:

q = a1 * (pHz - DI pH) + a2 * (pHz - DI pH)^2 + a3 * (pHz - DI pH)^3

The problem really is the implementation of A.J.'s calculations into a sheet that the average brewer can use. I understand the logic and it's implementation (at least I think I do) and use it in my own personal sheet. However, a lot of the background stuff would make people's eyes glaze over and eliminating the solver (which mine still uses) in favor of A.J.'s iterative solution in the background is still a work in progress.

So short story long, I would just double check on your implementation. You have to take into account the acidity of the mash somewhere, either with a color proxy or with the q equation above. Without it, Grist pH will just equal the sum of weighted DI pH, and you won't be telling yourself or anybody else anything of substance.

In the end, I'm not out to you-know-what on anyone's progress on this topic. I just want to make sure people are clear on the implementation. We now have a whole slew of pH estimation calculators that are all doing some slightly different form of the same thing: color based pH estimation.

If one gets better they all get better but it's important to agree on at least this fact: all current options are color based. That's not a bad thing but it still implies color as a proxy for actual acidity.

 

[ajdelange]

The Gen II approach (don't think we can glorify it to the extent of calling it a "specification") is to use robust models for everything in the mash (water, alkalinity, additions, grains) and thereby eliminate the inaccuracies that arise when corners are cut for simplicity and when empirical approaches are used or, at least, to do this to the extent possible. If we have not taken measurements on a grain, for example, we will have to use an empirical approach to obtaining the grain's characteristics such as comparing it to a similar grain or using measurements made by someone else. Thus practically we can seldom entirely eliminate empiricism in the grain model but we can eliminate it from the remainder of the process. Our results are thus improved relative to programs that model the grains empirically and use empirical or approximate models for the chemistry.

The acids, bases, water and alkalinity are all pretty straight forward so the whole thing turns on the
q = a1 * (pHz - DI pH) + a2 * (pHz - DI pH)^2 + a3 * (pHz - DI pH)^3
model for charge change on malt. I tried to handle this in the same way I handled the other elements i.e. by providing functions which can be entered into an Excell spreadsheet in the same way as the functions that come with Excel out of the box. The hope was that some person or persons who knew how to put a user friendly spreadsheet together would be able to take these "engine" functions and assemble a sheet the average brewer could benefit from. That seems to be harder to do than I had hoped.