A thought experiment to test the general validity of available mash pH software

[Silver_Is_Money]

I'm asking for A.J. DeLange to provide his input here.

First Mash Scenario:
---------------------------
BIAB
No Sparge
No added mineralization
10 gal. DI Water
12.5 Lbs. of 1.7L European Pilsner malt

Second Mash Scenario:
--------------------------------
10 gal. DI Strike Water
10 Gal. DI Sparge Water
No added mineralization
25 Lbs. of 1.7L European Pilsner malt

Given the above, the question for A.J. DeLange is this:

If it is found that for scenario 1 above the adjustment required to mash at a nominal target pH of 5.4 is roughly 6 mL of 88% lactic acid, then can it be assumed in advance from this that for scenario 2 above the lactic acid adjustment required to hit the same 5.4 mash pH should be roughly 12 mL of 88% lactic acid?

Reason for asking: I've noticed that for the Brewers Friend online mash pH calculator and my Mash Made Easy spreadsheet the above relationship with regard to the requisite acid quantity addition doubling with grist weight doubling in order to hit the same mash pH target holds to be true, but for some other of such software it does not hold true, and for yet other of such software it does not hold to be even close to remotely true. I'm asking you to resolve this dilemma, as it seems to me to be a rather serious one.

 

[Silver_Is_Money]

The Kaiser Water Calculator can be added to those programs which double the acid required to achieve the target mash pH when going from scenario 1 to scenario 2.

I will refrain to mention the names of those calculators (spreadsheets) which fail (to totally fail) to maintain this ratio, as it may simply be due to my misunderstanding of how to properly use them, or it may be due to their having knowledge that I do not posses (which is where A.J. DeLange comes in). Others are however clearly free to report their scenario related results for the software of their choice.

 

[ajdelange]

Looking at the fundamentals we have, in the first case:
10 gal DI water that needs to be brought to pH 5.4. That's going to take about 0.15 mEq of protons;
12.5 pounds of pale malt that needs to be brought to pH 5.4. That's going to take about 56.595 mEq (depending on the particular malt) of protons.
The total acid requirement is then 56.746 / 13.0 = 4.362 mL of 88% lactic acid (13.0 is the normality of 88% lactic acid to pH 5.4).

We have, in the second case:
10 gal DI mash water that needs to be brought to pH 5.4. That's going to take about .15 mEq of protons;
25 pounds of pale malt that needs to be brought to pH 5.4. That's going to take about 113.19 mEq (depending on the particular malt) protons which is exactly double the scenario 1 malt prton requirement.
The total acid requirement is then 113.34 / 13 = 8.714 mL of 88% lactic acid which
which is about double but not quite on the assumption that we did not treat the sparge water. If we treated the sparge water too then the acid requirement for the water would double, the acid requirement for the malt would double and the total would double.

If you are not getting this result with a spreadsheet or calculator and you are certain you are entering data into it correctly then there is a serious flaw in that spreadsheet or calculator. I am confident that Kai understands the underlying chemistry and am not, therefore, surprised that his calculators work. I have very little feeling for what other authors do though as I have seen statements from some of them to the effect that mash pH cannot be calculated effectively using pHDI as the basis for the calculation I am not very confident that they do understand the chemistry to the extent necessary to produce a solid product. I think most use a combination of some chemistry and some empiricism. But any of them should understand that acid demand is extensive (is directly proportional to the amount of material being acidified).

[Edit] There were errors in the original version of this post related to a problem in the main spreadsheet I use with regard to calculating the normality of lactic acid and sloppiness on my part in entering the alkalinity of DI water. The values here were computed using the new, compact spreadsheet posted later on in this thread.

 

[Silver_Is_Money]

Thank you kindly A.J.!

For one of the popular currently available spreadsheets I tried, the mL's of acid required to hit the 5.4 target mash pH actually went down slightly when the base malt concentration was doubled to alter the input criteria from scenario 1 to scenario 2. This presumes that I'm using the software as intended.

Or in other words (and again, presuming that I'm properly using the software), if the acid to be added for scenario 1 was left to be a constant when moving to scenario 2, the softwares resultant mash pH projection actually went down a wee bit in conjunction with the doubling of the low Lovibond base malt.

 

[Silver_Is_Money]

As to my own software, it currently does not consider the very small amount of acid that is required to move the DI strike water to the target of pH 5.4, so this results in an error for my spreadsheet of ~2%, since (when tweaked as per the below paragraph) my software predicts 5.00 mL of 88% Lactic Acid transitioning to 10.00 mL (as opposed to your more correct answer of 5 mL transitioning to 9.89 mL) with the grist weight doubling. In other words, my software does not begin to consider the acid required of the very strike water itself (to move it to the desired mash pH target) until alkalinity is present. An error that you have just made me aware of. But with only 2% induced error for the highly specific case of DI water (and given all of the other variables being internally juggled by the software) I'm wondering if this small level of error for the case of DI strike water would fully justify a future upgrade for my software.

PS: I initially derived my educated guesses of ~6 mL and ~12 mL for the case of the base malt having a presumed DIpH of 5.8. If I lower the presumed DIpH of the base malt just slightly, to about 5.73, then I get your 5 mL figure for scenario 1, and 10 mL for scenario 2.

 

[Silver_Is_Money]

The way I'm doing it, the spreadsheet which I'm referring to only as the "highly popular software" says it requires ~6.2 mL of 88% Lactic Acid for scenario 1 (with 12.5 Lbs. of 1.7L base malt), and ~5.7 mL of Lactic Acid for scenario 2 (with 25 Lbs. of 1.7L base malt), both to reach a final mash pH target of 5.4. Has anyone who may know more about using this popular software determined if I'm getting results that match theirs? I clearly may be doing something incorrectly.

 

[ajdelange]

As to my own software, it currently does not consider the very small amount of acid that is required to move the DI strike water to the target of pH 5.4, so this results in an error for my spreadsheet of ~2%,

My feelings on this are that the couple of % error from not considering the alkalinity of the water itself, the couple of percent from modeling malt buffering as a constant, the couple of percent from assuming that malt buffering is linear, the couple percent from not considering that bicarbonate's proton absorbing potential depends on pH, the couple percent from not recognising that lactic acid's proton donating capacity depends on mash pH, the couple percent from assuming that bicarbonate is a fixed fraction (61/50) of alkalinity and the error from ignoring (smaller than the others) ionic strength effects all add (or rather rss) up and that since we have powerful computing in our hands we might as well attack those error sources and knock them out. There are so many other places to incur error in brewing that I prefer to feel confident in my calculations at least. There are those that will argue that the accuracy improvement gained by considering ionic strength, given the other error sources, does not justify the substantial extra spreadsheet area ionic strength calculation requires, and so on for any of the other error sources I've mentioned and they might be right. Different philosophies I guess.

 

[Silver_Is_Money]

I'm already in the process of testing a revision (made only so far to the standard/avoirdupois version of 'MME') which gives as its output 5.00 ml of Lactic Acid for Scenario 1 (when the DIpH is tweaked slightly for the base malt to permit this exact output), and then subsequently yields 9.89 mL of Lactic Acid as the output for Scenario 2. After I kick the tires on this revision some more to assure that I didn't break something along the way, and also after I get it up and running on the metric version, I will release it as V_1.50 of Mash Made Easy. Thank you again A.J.

 

[ScrewyBrewer]

For one of the popular currently available spreadsheets I tried, the mL's of acid required to hit the 5.4 target mash pH actually went down slightly when the base malt concentration was doubled to alter the input criteria from scenario 1 to scenario 2. This presumes that I'm using the software as intended.

Or in other words (and again, presuming that I'm properly using the software), if the acid to be added for scenario 1 was left to be a constant when moving to scenario 2, the softwares resultant mash pH projection actually went down a wee bit in conjunction with the doubling of the low Lovibond base malt.

I noticed when 12.5 lbs of grain are mashed in 10 gallons of treated water the mash thickness is 3.2qt/lb. And when 25 lbs of grain are mashed in 10 gallons of treated water the mash thickness is 1.6qt/lb. There is a correlation between mash liquor-to-grist ratio and mash pH.

 

[Silver_Is_Money]

I noticed when 12.5 lbs of grain are mashed in 10 gallons of treated water the mash thickness is 3.2qt/lb. And when 25 lbs of grain are mashed in 10 gallons of treated water the mash thickness is 1.6qt/lb. There is a correlation between mash liquor-to-grist ratio and mash pH.

Agreed. Kai Troseter researched this extensively back in about 2008/2009. But I believe this is merely another way of expressing the outcome of that which A.J. detailed in his first post above. I.E., Kai's observation that thinner mashes show a bit higher mash pH than thicker mashes, and therefore thinner mashes require more acid per pound of grist vs. thicker mashes is fully reflected in A.J.'s solution seen above, wherein the Scenario 1 thinner mash needs 5.00 mL of lactic acid for 12.5 lbs. of grist, but the scenario 2 thicker mash requires only 9.89 mL of lactic acid (as opposed to an intuitive first assumption of 10.00 mL), despite having fully twice as much malt which must be titrated to reach the the mash target of 5.4 pH.

Clearly though, for the case of DI (and also quality distilled or high quality RO) water, the effect is generally rather small. And as strike water alkalinity increases, it eventually dwarfs this small effect.

 

[ajdelange]

My take on the mash thickness question is that if you have water with alkalinity x and mash with L liters of it then you will introduce L*x units of alkalinity into the mash and, in most cases, require 0.9*L*x units of acid. If you mash with 1.2*L liters of water you will introduce 1.2*L*x units of alkalinity and require, again nominally, 0.9*1.2*L units of acid i.e. 20% more to reach the same pH. If you don't add the extra acid the pH will be higher.

 

[ScrewyBrewer]

Interesting enough using 12.5 lbs of grain and halving the mash water from 10 gallons [3.2qt/lb] to 5 gallons [1.6qt/lb] the acid addition needed to hit 5.4pH drops from 6ml to 2.7ml.

Where doubling the grain to 25 lbs and using 10 gallons of water [1.6qt/lb] the acid addition needed to hit 5.4pH drops from 6ml to 5.4ml.

 

[Silver_Is_Money]

Interesting enough using 12.5 lbs of grain and halving the mash water from 10 gallons [3.2qt/lb] to 5 gallons [1.6qt/lb] the acid addition needed to hit 5.4pH drops from 6ml to 2.7ml.

Where doubling the grain to 25 lbs and using 10 gallons of water [1.6qt/lb] the acid addition needed to hit 5.4pH drops from 6ml to 5.4ml.

Something appears seriously amiss here. In paragraph 1 are you considering specifically the case for mashing in DI strike water, or in strike water with Ca++ and Mg++ ions present? The ppm concentration of these two ions would double if the same amount of mineralization was to be added to 5 gallons of strike water as for 10 gallons. But even then the downward shift in pH due to the presence of these ions would not nearly change the acid titrant requirement as much as you are indicating.

Paragraph 2 loses me completely. Twice as much to be titrated requires twice as much titrant, or as A.J. detailed, a wee bit less than twice for the real world case wherein twice as much DI water carrier is not also added. If 12.5 Lbs. of grist requires 6 mL of acid titrant, then 25 Lbs. will require fractionally a wee bit less than 12 mL of acid titrant.

This whole mess has me wondering how on earth so many home brewers can claim that they are consistently hitting measured mash pH's which are within 0.1 (or better) of their popular softwares projected mash pH target. Is confirmation bias that powerful a force?

 

[ScrewyBrewer]

Something appears seriously amiss here. In paragraph 1 are you considering specifically the case for mashing in DI strike water, or in strike water with Ca++ and Mg++ ions present?

The examples I posted used RO water treated with 88% lactic acid. No other mineral additions were made. I would never bet money on predicted pH coming within ~0.1 of actual pH 100% of the time. Although it does feel rewarding when it does happen. Writing down the predicted pH and the actual pH of each new recipe is a good idea. This way adjustments can be factored in accordingly if the mash pH drifts too far from the predicted pH. By the second or third time brewing that same recipe chances of coming within ~0.1pH are much higher.

 

[ScrewyBrewer]

The ppm concentration of these two ions would double if the same amount of mineralization was to be added to 5 gallons of strike water as for 10 gallons. But even then the downward shift in pH due to the presence of these ions would not nearly change the acid titrant requirement as much as you are indicating.

Paragraph 2 loses me completely. Twice as much to be titrated requires twice as much titrant, or as A.J. detailed, a wee bit less than twice for the real world case wherein twice as much DI water carrier is not also added. If 12.5 Lbs. of grist requires 6 mL of acid titrant, then 25 Lbs. will require fractionally a wee bit less than 12 mL of acid titrant.

This whole mess has me wondering how on earth so many home brewers can claim that they are consistently hitting measured mash pH's which are within 0.1 (or better) of their popular softwares projected mash pH target. Is confirmation bias that powerful a force?

Agreed. When using 'popular' spreadsheet calculations on your example 1 and 2 scenarios something does seem off. When using DM Riffe's calculations on your example scenarios the predicted pH comes closest to AJ's.

 

[Silver_Is_Money]

Agreed. When using 'popular' spreadsheet calculations on your example 1 and 2 scenarios something does seem off. When using DM Riffe's calculations on your example scenarios the predicted pH comes closest to AJ's.

Have you tried the scenarios with 'Mash Made Easy' version 1.50?

PS: As for the impact of mineralization upon the downward shift in mash pH, the buffering modification permitted by 'MME' (with user input values ranging from 30 to 50) alters the degree of downward mash pH shift witnessed by the concentrations of Ca++ and Mg++ ions present in the strike water. This flexibility is there to permit you to dial in 'MME' to reflect your real world measurements of the mash pH impact of specifically strike water mineralization. This feature is more for advanced users, but it is very easy and intuitive to use, even for the novice. Many will chose to ignore this feature and be quite happy, but the perfectionists will enjoy playing with it. Just another tool to allow you to dial in the output of 'MME' to reflect your measured reality to a higher degree. Lower buffering set-point values cause greater downward mash pH shift from added calcium and/or magnesium, and higher set-point values do the opposite. The base malt type modifier (a drop down located in the lower right corner, which alters the DIpH profile of the grists primary low Lovibond color base malt(s) if present), is yet another 'dial in' tool of great importance in permitting the output of 'MME' to more closely reflect reality (with the ultimate and most advanced adjustment in this fine tuning camp being the direct DIpH override feature, which once again is there primarily for the more advanced end users who are capable of directly measuring DIpH values for their individual grist components). But notice in all of this that reality trumps software, which can only be trained to 'better' reflect reality. One must never get to the point of accepting that software possesses a reality that trumps measured reality, as software of this type has within it only math models designed to 'hopefully' reflect reality. One must ask if their chosen software even allows for the flexibility of such critical end user modifications as these.

 

[ScrewyBrewer]

Have you tried the scenarios with 'Mash Made Easy' version 1.50?....

....But notice in all of this that reality trumps software, which can only be trained to 'better' reflect reality. One must never get to the point of accepting that software possesses a reality that trumps measured reality.

I will give MME a try this week. Thank you for sharing.

 

[mabrungard]

Reason for asking: I've noticed that for the Brewers Friend online mash pH calculator and my Mash Made Easy spreadsheet the above relationship with regard to the requisite acid quantity addition doubling with grist weight doubling in order to hit the same mash pH target holds to be true, but for some other of such software it does not hold true, and for yet other of such software it does not hold to be even close to remotely true. I'm asking you to resolve this dilemma, as it seems to me to be a rather serious one.

Its sad that you hadn't spent any time understanding the acidification needs for both the mashing and sparging water. They are markedly different.

In the second scenario, the 10 gallons of DI sparging water requires no acid at all since it has zero alkalinity. The mashing water needs are quite different since the buffering of the malt system must be overcome to produce a desirable mashing pH. Any software that indicated that twice the acid should be used in scenario 2 for the 10 + 10 gallons of DI water, is quite wrong.

The water/grist ratio does play a critical factor in what a mash's pH will be. All one has to do is look at the systems at work in the mash to surmise that. If the water has X mEq/L alkalinity and there are Y liters of mashing water, then there is a need for XY mEq of protons from an acid to fully neutralize that alkalinity. In addition, the buffering system within the malt requires A mEq/kg of acid protons to produce a desired pH and the malt mass of B kg means that a total of AB mEq of acid protons are needed. The total acid demand is (XY + AB) mEq.

The scenario above is simplified when zero alkalinity DI water is employed. The acid demand becomes AB mEq. When the mashing water volume is altered, the acid quantity AB remains unchanged in the scenario. Since pH is the concentration of protons in solution, it should be apparent that altering the mash's water/grist ratio will proportionally alter the pH. When alkalinity is present in the mashing water, it should again be apparent that additional acid protons are required when the quantity of water is increased. Software that doesn't reflect that water/grist ratio pH variation would not be very accurate.

I trust these explanations will help you understand the errors in your thought experiment.

 

[Silver_Is_Money]

For the admittedly rather extreme scenario altering case being discussed here, my thought experiment was only off by about 2% as confirmed by A.J. DeLange.

Although admittedly acidic, 1.7L Pilsner base malt can effectively be considered to be basic with respect to a mash pH target of 5.4, seeing as its DIpH is on the order of 5.8, and therefore it requires acidification to move it to a pH of 5.4 during and within the mash. And moving twice the quantity of just such a grist to a mash pH of 5.4 (in the presence of DI strike water only, and with no added mineralization) requires very nearly twice the acid. The end result is that the grist doubling proves for the case wherein scenario 1 requires 5 mL of 88% lactic acid, this assuredly transitions to 9.89 mL of the same acid for scenario 2. I have subsequently rectified my openly admitted oversight of this matter in 'MME', but at least one other popular software 'potentially' does not agree that A.J.'s solution (I.E., that the mL's of required acid required for a transition from scenario 1 to scenario 2 must nigh on double) is close to correct at all.

I can now add that EZ Water comes fairly close to agreeing with A.J.'s assessment. Not quite, but leagues better than the other of available popular software.

Martin, what is your software's solution with respect to the mL's of 88% lactic Acid required to mash at a pH of 5.4 for strict adherence to the criteria for both of the scenarios which are being discussed here? And if it is radically different from A.J.'s solution, what justification would you offer as to an explanation for the discrepancy?

PS: There has been no discussion at all in this thread with respect to acidifying sparge water, so why attempt to confound and confuse matters by bringing that up?

 

[ajdelange]

In the second scenario, the 10 gallons of DI sparging water requires no acid at all since it has zero alkalinity. The mashing water needs are quite different since the buffering of the malt system must be overcome to produce a desirable mashing pH. Any software that indicated that twice the acid should be used in scenario 2 for the 10 + 10 gallons of DI water, is quite wrong.

In scenario 2, as you say, the 10 gal of sparge water requires no (actually not 0 but very little) acid as it has very little alkalinity. But the same is true of the mash water - it doesn't require any (or only very little) acidity either. The only acid requirement in Scenario 2 is that of the malt.

In Scenario 1 the 10 gal of DI mash water doesn't require any acid any more than the . The entire acid requirement is that of the malt. In scenario 2 there is twice as much malt as in scenario 1 so twice as much acid is required for the malt. It is thus clear as the azure sky of a summer's day that any software that doesn't say that scenario 2 requires twice as much acid is seriously in error to the point that I can't believe that Bru'n water nor any other program would, in response to the doubling of the amount of malt entered, respond with the admonition to add less acid. The data has to have been entered wrong.

 

[mabrungard]

In scenario 2 there is twice as much acid as in scenario 1 so twice as much acid is required. It is thus clear as the azure sky of a summer's day that any software that doesn't say that scenario 2 requires twice as much acid is seriously in error to the point that I can't believe that Bru'n water nor any other program would, in response to the doubling of the amount of malt entered, respond with the admonition to add less acid. The data has to have been entered wrong.

AJ, I'm not sure what your saying above???

 

[ajdelange]

First we have to agree that if one is mashing with DI water which we consider to have 0 alkalinity that the amount of acid required is proportional only to the amount of malt such that if one considers two mashes one of which contains twice the amount of malt as the other then one with the larger amount of malt will require twice the acid irrespective of the amount of water (within reason). Then what I went on to try to say is that given the obvious truth of this premise I don't see how it would be possible to write a program which contradicts it and, therefore, no program actually does. If that premise is also true then when one approaches a program, enters Scenario 1 and Scenario 2, and finds that the acid required for Scenario 2 is not about twice that for Scencario 1 we are forced to conclude that he must not have entered the data properly.

 

[Silver_Is_Money]

With Bru'n Water I get 6.2 mL of 88% lactic acid as the solution for scenario #1, and 5.8 mL of the same acid as the solution for scenario #2. These being the minimum quantities of 88% lactic acid required to bring the mash to 5.4 pH for 12.5 Lbs. of 1.7L base malt, and for 25 Lbs. of 1.7L base malt respectively. These solutions are identical for both the free and the pay version. I even downloaded a fresh copy of the free version which came with fields set to zero

As far as I can tell I am entering all data properly to meet the specifics called for by each scenario. All minerals show zero ppm. Total anions zero. Total cations zero. Mash water for both scenarios is set at 10 gallons. Sparge water for scenario #1 is set at zero, and for scenario #2 is set at 10 gallons. The input data is seemingly correct.

I must now ask for anyone who routinely uses this program to please tell me if the results I'm getting are also the results that you are getting for my scenario #1 and scenario #2 input criteria. Either I'm not entering the scenario input data correctly, or something within the underlying programming of the spreadsheet is radically in error.

 

[ScrewyBrewer]

.....anyone who routinely uses this program to please tell me if the results I'm getting are also the results that you are getting for my scenario #1 and scenario #2 input criteria. Either I'm not entering the scenario input data correctly, or something within the underlying programming of the spreadsheet is radically in error.

I've spent some time using your two original scenarios and comparing the results from several water calculators. I found obvious differences between their pH predictions when using a single grain and lactic acid to lower pH. I then tried entering a real world recipe in several different water calculators.

Scenario #3: 20 pounds of Pilsner(2L), 1 pound of Vienna(4L) malt mashed in 12 gallons of RO water treated with 2g CaCl2 and 3g(MgSO4).

The pH prediction results of the calculators tested are as follows:

lactic acid = 6.65ml Mash pH = 5.38 [Mash Made Easy v1.50]
lactic acid = 6.65ml Mash pH = 5.38 [Bru'n Water v118]
lactic acid = 6.65ml Mash pH = 5.43 [ezRecipe v1.21]
lactic acid = 6.65ml Mash pH = 5.47 [EZ Watercalculator v3.0.2]
lactic acid = 6.65ml Mash pH = 5.50 [MpH Water Calculator v3.0]


I'm not ready to draw any conclusions yet as to why these results are this way. I find it interesting that the wide discrepencies found when using the original scenarios are not present in Scenario #3. I will look a bit deeper once I find the time though.

 

[Silver_Is_Money]

ScrewyBrewer, for your "Scenario #3" input criteria I get the following:

lactic acid = 8.35 mL for mash pH = 5.40 [Mash Made Easy v1.50]
lactic acid = 5.90 mL for mash pH = 5.40 [Bru'n Water v118]
lactic acid = 8.20 mL for mash pH = 5.40 [EZ Water Calculator v3.0.2]
lactic acid = 10.30mL for mash pH = 5.40 [MpH Water Calculator v3.0]
lactic acid = 9.10 mL for mash pH = 5.40 [ezBrewingWater-RO v2.0]

For the 20 lbs of Pilsner base malt I used the following criteria:
-----------------------------------------------------------------------------------
MME was set to: 2L North American Pilsner, which defaults to DIpH = 5.75
Bru'n Water was set to its default for 2L base malt, default DIpH unknown
EZ Water was set to selector #2, which was adjusted to 5.75 DIpH (to correlate with MME and ezBW-RO)
MpH was set to its default for 2L base malt, DIpH unknown
ezBrewingWater-RO was set to Pilsner malt, which defaults to DIpH = 5.75

***MME was also left at its factory default buffering value of 32, which allows for a relatively higher downward shift in pH due to mineralization. The lactic Acid required for MME would likely have moved more toward the results for ezBW-RO and MpH if I had selected a higher buffering value of say 45 to perhaps 50 here instead.

Bru'n Water still appears to be relatively the odd man out here.

 

[Big Monk]

See below:

ScrewyBrewer, for your "Scenario #3" input criteria I get the following:

lactic acid = 8.35 mL for mash pH = 5.40 [Mash Made Easy v1.50]
lactic acid = 5.90 mL for mash pH = 5.40 [Bru'n Water v118]
lactic acid = 8.20 mL for mash pH = 5.40 [EZ Water Calculator v3.0.2]
lactic acid = 10.30mL for mash pH = 5.40 [MpH Water Calculator v3.0]
lactic acid = 9.10 mL for mash pH = 5.40 [ezBrewingWater-RO v2.0]

For the 20 lbs of Pilsner base malt I used the following criteria:
-----------------------------------------------------------------------------------
MME was set to: 2L North American Pilsner, which defaults to DIpH = 5.75
Bru'n Water was set to its default for 2L base malt, default DIpH = 5.75
EZ Water was set to selector #2, which was adjusted to 5.75 DIpH (to correlate with MME and ezBW-RO)
MpH was set to its default for 2L base malt, DIpH = 5.72
ezBrewingWater-RO was set to Pilsner malt, which defaults to DIpH = 5.75

***MME was also left at its factory default buffering value of 32, which allows for a relatively higher downward shift in pH due to mineralization. Lactic Acid would likely have moved more toward ezBW-RO and MpH if I had selected a higher buffering value of say 45 to 50.

Bru'n Water still appears to be relatively the odd man out here.

MpH with a weighted DI pH input for all base malts and 0.17 substituted for it's calculated pH/RA slope term (ala BW) is the best thing going IME. For the No-Sparge brewing I do, and fairly constant grain amounts and water amounts, it gives the best results.

I just crunched the numbers of SB's Scenario 3 and got 7.10 ml of 88% Lactic to hit 5.40 pH from my personal sheet, which is modified as stated above.

 

[Silver_Is_Money]

RPIScotty, what does your personally modified MpH spreadsheet yield for specifically the scenario #1 and scenario #2 criteria which started this thread?

 

[Silver_Is_Money]

So to look at scenario #3 from the perspective of scenario #2 (it's closest DI water match) we have to believe the following:

1) A.J. determined 9.89 mL of 88% Lactic Acid required for scenario #2, and Brewer's Friend (and now Mash Made Easy) fully agree.
2) Screwy subsequently took out 5 Lbs. of Pilsner malt, added back in 1 Lb. of Vienna malt, and also tossed in 3 g. of MgSO4 and 2 g. of CaCl2. He also added 2 gallons of additional strike water. He labeled this revision "Scenario #3".

MME transitioned from 9.89 mL of Lactic Acid as the solution for scenarion#2, to 8.35 mL as the solution for #3.
Some others it seems have transitioned all the way down to 5.9 mL or even 5.5 mL of Lactic Acid for scenario #3.

In the big picture of things, the small additions of minerals must be working miracles to cut the acid requirement nearly in half, for what amounts to a grist that has only been reduced from 25 Lbs. to 21 Lbs., and which remains as primarily Pilsner malt. I just can't imagine such a dramatic shift, as opposed to a more sensible shift of 9.89 mL transitioning to 8.35 mL of Lactic Acid when moving from scenario #2 to scenario #3.

 

[Big Monk]

RPIScotty, what does your personally modified MpH spreadsheet yield for specifically the scenario #1 and scenario #2 criteria which started this thread?

For Scenario #1 - 6.75 ml 88% Lactic Acid

For Scenario #2 - I don't have sparging in my sheet

For Scenario #3 - 7.10 ml 88% Lactic Acid

 

[Silver_Is_Money]

RPIScotty: Sparging is irrelevant to what is going on during the mash. No need to consider it as a factor here.

And as an aside (which does not add or alter any relevance) for DI or RO no acid would likely be added to the sparge water to begin with.

Set your software up again as for scenario #1 and then simply alter 12.5 Lbs. of Pilsner to 25 Lbs. of Pilsner and call it scenario #2.

 

[Silver_Is_Money]

It just dawned upon me that to keep this more on the level of "apples to apples" for MME, it must be said that to get precisely 5.00 mL of Lactic Acid transitioning to 9.89 mL (from scenario 1 to 2), I used the manual DI pH override feature and selected ~5.72 as the DI pH, whereas for scenario #3, in order to keep things more equal with respect to a few of the other available programs, I bumped the DIpH of the Pilsner up to 5.75 when I ran MME with scenario #3. If I had kept it at 5.72 for scenario #3 instead, the output would have been a smidge less than the 8.35 mL of lactic Acid which I reported above as the solution for MME in conjunction with scenario #3.

 

[Big Monk]

RPIScotty: Sparging is irrelevant to what is going on during the mash. No need to consider it as a factor here.

And as an aside (which does not add or alter any relevance) for DI or RO no acid would likely be added to the sparge water to begin with.

Set your software up again as for scenario #1 and then simply alter 12.5 Lbs. of Pilsner to 25 Lbs. of Pilsner and call it scenario #2.

For Scenario #1 - 6.75 ml 88% Lactic Acid

For Scenario #2 - 7.10 ml 88% Lactic Acid

For Scenario #3 - 7.10 ml 88% Lactic Acid

*Note: I have the DI pH for the Pils malt set at 5.75

 

[Silver_Is_Money]

Thanks much RPIScotty!!!

 

[Big Monk]

Thanks much RPIScotty!!!

No sweat. Just to be clear, my sheet is as follows:

1.) Based primarily on the Riffe MpH sheet;
2.) Removes his pH/RA slope term and replaces it with the BW constant 0.17;
3.) Uses weighted average of DI pH for each base malt used (all base malts have separate inputs in the fermentables database);
4.) Models Sauergut as low acid % Lactic;
5.) Uses the Sauermalz calculations from Kai's sheet;
6.) Accounts for pH and mineral changes from antioxidants;
7.) Calculates Kettle acid additions as well as knockout additions for Sauergut and mineral acids;
8.) Has pH override cells for adjusting on the fly (not recommended unless way off but there anyway)

So basically a mutt but really a marriage between BW and MpH with our own little flair added in.

 

[ScrewyBrewer]

For Scenario #3 I used ezRecipe v1.21 instead of ezBrewingWater-RO v2.0.

lactic acid = 5.90 mL for mash pH = 5.40 [Bru'n Water v118]
lactic acid = 7.10 mL for mash pH = 5.40 [RPIScotty]
lactic acid = 7.60 mL for mash pH = 5.40 [ezRecipe v1.21] shown below.
lactic acid = 8.20 mL for mash pH = 5.40 [EZ Water Calculator v3.0.2]
lactic acid = 8.35 mL for mash pH = 5.40 [Mash Made Easy v1.50]
lactic acid = 9.10 mL for mash pH = 5.40 [ezBrewingWater-RO v2.0]
lactic acid = 10.30mL for mash pH = 5.40 [MpH Water Calculator v3.0]

 

[Silver_Is_Money]

I re-ran scenario #3 with 'MME' for the specific case of the 20 Lbs. of Pilsner malt set to a manual override DIpH of 5.72.

I then got the following output for scenario #3:
------------------------------------------------------------
1) With buffering set at 32, the requirement to hit 5.4 pH for the mash was 7.58 mL of 88% Lactic Acid (the buffering default)
2) With buffering set at 40, the requirement to hit 5.4 pH for the mash was 7.70 mL of 88% Lactic Acid
3) With buffering set at 45, the requirement to hit 5.4 pH for the mash was 7.76 mL of 88% Lactic Acid
4) With buffering set at 50, the requirement to hit 5.4 pH for the mash was 7.80 mL of 88% Lactic Acid

As can be seen, the scenario #3 output difference between ezRecipe, Scotty's personally modified MpH spreadsheet, and Mash Made Easy has narrowed a bunch if I use 5.72 as the DIpH for the Pilsner instead of 5.75. There is little difference at all between ezRecipe and MME for this highly specific case.

Can ezRecipe handle strike waters with beginning analyticals that are other than RO (distilled, DI)?

 

[Big Monk]

Now we just need someone to brew these beers and measure with a calibrated meter at 20-25 minutes into the mash and report the results with no bias and well be good.

 

[ajdelange]

I think of may have found (by careful reading of his last post - which, be honest guys, we don't always do) the problem in Martin's reasoning which could be responsible the problem you guys are seeing with Bru'n water. They key paragraph is

The scenario above is simplified when zero alkalinity DI water is employed. The acid demand becomes AB mEq. When the mashing water volume is altered, the acid quantity AB remains unchanged in the scenario.

So far, so good.

Since pH is the concentration of protons in solution, it should be apparent that altering the mash's water/grist ratio will proportionally alter the pH.

Now here's where we run into trouble. It would seem that he is assuming that the added protons (AB mEq of them) are distributed between the malt and the water in a way other than the way they actually are. The bases in the malt (lets throw out doubly dissociated succinate with its second pK of 5.6 as an example: H+ + Suc-- --> HSuc-) are much stronger bases than water is and so they grab the lion's share of the protons with only a small fraction going to protonate water. The quantity taken by the water is approximately 1000*(10^(-pHz) - 10^(-pHs)) in which pHz and pHs are, respectively, the pH at which the water ultimately arrives. It is computed by choosing a trial pH, determining the charge on the water and the charge on the malt bases. The sum must be 0. If it is greater than 0 the pH is too low and another, higher pH is tried. If it is negative then the trial pH is too high and a lower pH is tried until the value which zeroes the charges is found. This is the pH at which the mash will settle.

As indicated in my first response to the OP about 57.2 mEq of protons would be needed for the first scenario of which only 1.2 mEq go to protonate water (H+ + H2O --> H3O+; pH is approximately the concentration of H3O+). The remaining 56 go to protonate molecules of malt bases (H+ + malt_ate- --> Hmalt_ate).

If the amount of malt is doubled but the amount of water left the same the requirement for the malt doubles to 112 but the requirement, for the same pH, for the water remains the same: 1.2 mEq. If the amount of water is also doubled then another 1.2 mEq of protons will be needed to acidify that second 10 gal water to pHz, the target pH. This makes the total requirement 114.4. So, in fact, increasing the amount of DI water used in a mash does make a wee difference (because even DI water has alkalinity) but as the fraction that goes to the water is so small it can be ignored in back-of-the-envelope calculations.

When alkalinity is present in the mashing water, it should again be apparent that additional acid protons are required when the quantity of water is increased. Software that doesn't reflect that water/grist ratio pH variation would not be very accurate.

In the case of DI water the variation in water to grist ratio can be ignored to quite good accuracy. Ignoring the water's requirement causes an error of 1.2/57.2 = 2.1% in Scenario 1. I chase errors of that magnitude and so include the water component in all my alkalinity calculations. Others don't.

Thus when Martin says that even with DI water a program than ignores mash thickness "would not be very accurate" it hints that he doesn't understand what it written above (which he really, really, needs to understand) but it does not explain how his program comes up with no increased acid requirement when malt doubles. Is he somehow conflating malt alkalinity and water alkalinity? I really don't know but think that his problem must be rooted in that part of the forest.

 

[ajdelange]

Scenario #3: 20 pounds of Pilsner(2L), 1 pound of Vienna(4L) malt mashed in 12 gallons of RO water treated with 2g CaCl2 and 3g(MgSO4).

The pH prediction results of the calculators tested are as follows:

lactic acid = 6.65ml Mash pH = 5.38 [Mash Made Easy v1.50]
lactic acid = 6.65ml Mash pH = 5.38 [Bru'n Water v118]
lactic acid = 6.65ml Mash pH = 5.43 [ezRecipe v1.21]
lactic acid = 6.65ml Mash pH = 5.47 [EZ Watercalculator v3.0.2]
lactic acid = 6.65ml Mash pH = 5.50 [MpH Water Calculator v3.0]

lactic acid = 6.65ml Mash pH = 5.35 Weyermann's pneumatic Pils
lactic acid = 6.65ml Mash pH = 5.46 Weyermann's floor Pils
lactic acid = 6.65ml Mash pH = 5.51 Rahr Pils

From which we might conclude that Bru'n water and Mash Made Easy model "Pilsner (2L)" close to Weyermanns pneumatic pils; that the later version of MME models it closer to Rahr puls and that ezRecipe and EZ Watercalculator model it close to Weyermanns floor pils. But the program that came up with these latter pH measures also
1)Recognizes that water itself has alkalinity which must be separately accounted for
2)The proton donating capacity of lactic acid depends on the pH
3)That the calcium/phytin reaction does not complete in the mash tun. The calculations assume that it is half completed in the mash tun.

I'm not ready to draw any conclusions yet as to why these results are this way. I find it interesting that the wide discrepencies found when using the original scenarios are not present in Scenario #3. I will look a bit deeper once I find the time though.

The only possible conclusion is the one we return to over and over:the different programs model the malts (and other mash components) in different ways and thus come up with different answers for the same set of inputs.

 

[Big Monk]

The only possible conclusion is the one we return to over and over:the different programs model the malts (and other mash components) in different ways and thus come up with different answers for the same set of inputs.

Bingo Bango.