Make the Water Calc for both Mash & Boil - a total brew calc

[Mont Y. Märzen]

[Maybe this should be under Calculator Support, but I suspect it is working as designed, so I'm putting it under Feature Requests.]

I sometimes need to hold back some or all of my salts to the boil, so as not to drop pH too far. And while I understand moving those additions to the kettle do not affect Mash pH, they do affect Boil pH. It would be nice to see what effect that will have when placed in the Sparge/Kettle section.

Also, when placed in the Sparge/Kettle section, the salts do not show any effect on the ion actuals to see if they are meeting the profile targets. So I have to enter them in the Mash section to dial them in, then move them. Certainly, even though they are post mash, they DO affect the flavor perceptions of the beer, which is why I'm adding them in the first place. As it stands currently, entering them in the Sparge/Kettle section gives me no feedback on their addition in any respect whatsoever.

It is as if the Water Calculator is designed only for mashing and completely disregards any later impact. It could be so much more useful otherwise.

In line with this, perhaps separate Sparge/Kettle sections are in order. While I do BIAB and don't sparge, it seems this section is really ignoring the 'Kettle addition' idea despite the name and treating this as just a Sparge addition. I noticed this because putting salts there, I get an error telling me I need a Sparge volume. But these were Kettle, not Sparge additions. The pre-boil volume should be used in that case for the ion concentration calculations. (I think this part is a bug/oversight/assumption, but I'll just keep it here for now. I can certainly start a different thread or report an issue if preferred.)

Having a separate Kettle section would also facilitate Boil pH acid adjustments as discussed in another Feature Request. The Calc would then provide two pH estimates, one for the Mash, and one for the Boil.

The ion summary should be separate for the Mash/Sparge/Kettle as appropriate.

 

[Silver_Is_Money]

We could go back to Kolbach's 1950's attempt to predict, target, and thereby be capable of advanced modification of knockout pH. His chosen calcium and magnesium "divisors" are probably much closer to the truth for knockout (I.E., post boil and cooling) pH conditions than they ever would be capable of being as tools whereby to predict well earlier mash pH.

That plus I'm convinced that in an earlier era of brewing, before homebrewing and the micro-brewery craze, the occasionally hinted at mash target ideal of 5.4 pH (give or take a smidge) was intended purely as a mash temperature measured target value, placing the room temperature measured mash pH ideal target closer to 5.6-5.65 pH.

A separate (or perhaps sole?) acidification was done back in the day targeting a post boil and cooling pH of 5.1-5.2 pH, and it was apparently done most often just prior to the juncture of adding fining agents to the boil, with this done to maximize hop bitterness and reduce the need for adding more hops, in addition to reducing the need for fining mass, with both reductions offering cost benefit in addition to operations benefit.

This would mean adjusting to 5.6-5.65 pH (at room temp) during the mash only if the likelihood of mashing at higher than this pH presents itself (whereby to justify this pre-mash adjustment step), and then adjusting to a room temperature measured boil pH of 5.1-5.2.

At a room temperature measured 5.2 (or lower) pH leading into the boil any additional (or further) pH drop that might occur across the boil will be minimal/minimized.

For darker brews mashing at a room temperature measured pH below ~5.2, adjusting pH upward a bit before the mash becomes a viable option to mitigate the acrid taste that often accompanies dark roasted malt acidity.

The higher the pH is leading into the boil the greater will be the magnitude of the measured pH drop across the boil. But by ~5 pH or below (as measured at room temperature) there should be no additional pH drop witnessed across the boil. Low pH at this juncture (I.E., the boil going below 5.1-5.2 pH as measured at room temperature) negatively impacts both boil added finings impact upon future clarity and currently occurring/ongoing boil induced hot break, which are both considered to be maximally optimized at a pH of ~5.2 (as measured at room temperature).

When the brewing masters of yore spoke of (and peer review documented) witnessing about 0.3-0.35 points of pH drop across the boil it was likely because they were entering the boil at a pH of about 5.6-5.65. That we only seem to measure a drop across the boil of 0.1-0.15 pH points in the current era is likely because we are entering the boil at a pH of 5.2 to 5.4 pH, as opposed to their 5.6-5.65 pH (if measured at room temperature). It is not because their instruments or methods were inferior. It might however indicate that our current methods are inferior.

 

[Mont Y. Märzen]

We could go back to Kolbach's 1950's attempt to predict, target, and thereby be capable of advanced modification of knockout pH. His chosen calcium and magnesium "divisors" are probably much closer to the truth for knockout pH conditions than they ever would be capable of being as tools whereby to predict well earlier mash pH.

That plus I'm convinced that in an earlier era of brewing, before homebrewing and the micro-brewery craze, the occasionally hinted at mash target ideal of 5.4 pH (give or take a smidge) was intended purely as a mash temperature measured target value, placing the room temperature measured mash pH ideal target closer to 5.6-5.65 pH.

I'm in agreement here. I think much of what we read that is touted as 'spec' is really just what someone wrote down centuries after the process was well established. And that didn't mean that was the definitive process, just what those folks had worked out and were doing at the time. Much of that they couldn't control in the slightest, but they chose to document it once they had the instruments to do so. (Thomas Jefferson thought the invention of the thermometer was going to be a huge boon to the serious brewer!) This would be analogous to watching your grandmother cooking and trying to measure out what she was putting in so you could document her recipes. She'd just shake her head and chuckle while she's trying to teach you how to recognize proportions and how food 'turns' when it is cooked the 'right' way.

A separate (or perhaps sole?) acidification was done back in the day targeting a post boil and cooling pH of 5.1-5.2 pH, and it was apparently done most often just prior to the juncture of adding fining agents to the boil.

This would mean adjusting to 5.6-5.65 pH (at room temp) during the mash if the likelihood of mashing at higher than this pH presents itself (whereby to justify this pre-mash adjustment step), and then adjusting to a room temperature measured boil pH of 5.1-5.2.

At a room temperature measured 5.2 (or lower) pH leading into the boil any additional (or further) pH drop that might occur across the boil will be minimal.

I've observed the same thing myself. I usually don't worry about pH as long as I'm in range for the Mash, but I do try to slightly overshoot 5.2 (that is, less than) for pre-boil and I see little change post-boil. Unfortunately, I didn't keep those stats, but I'll start doing so just for kicks. I guess that's why a pro-brewer advised me to adjust my pre-boil to just below 5.2 as that would greatly reduce the drop, assist with hop isomerization (allegedly) during the boil, and benefit break formation and clarity.

For darker brews mashing at a room temperature measured pH below ~5.2, adjusting pH upward a bit before the mash becomes a viable option.

For my source water, I've found this to only be a problem for Dark Brown or darker brews. (probably 25+ SRM) The adjustment here is easy, hold back the dark grains (+250L) for the Vourlauf/Lauter, or cold steep them in advance and add them at pre-boil.

The higher the pH is leading into the boil the greater will be the magnitude of the measured pH drop across the boil. But by ~5 pH or below (as measured at room temperature) there should be no additional pH drop witnessed across the boil. Low pH at this juncture (I.E., the boil going below 5.1-5.2 pH as measured at room temperature) negatively impacts both boil added finings impact upon future clarity and currently occurring boil hot break, which are both optimized at a pH of ~5.2.

That is interesting, because I've noticed better break and better clarity when I get it slightly below 5.2 rather than leave it higher or on point. I dare not drop it below 5.0 so I can't speak to that case. We did massively overshoot to 4.8 once, but noticed no issues thankfully.

When the brewing masters of yore spoke of witnessing about 0.3-0.35 points of pH drop across the boil it was likely because they were entering the boil at a pH of about 5.6-5.65. That we only seem to measure a drop across the boil of 0.1-0.15 pH points in the current era is likely because we are entering the boil at a pH of 5.2 to 5.4 pH, as opposed to their 5.6-5.65 pH. It is not because their instruments were inferior.

Makes sense so far.

 

[Silver_Is_Money]

I dug through Wiley Online and came across this 1975 brewing research document (see link below). See Table XI on page 68 at the bottom left. It shows that in their tests:

1) A Wort which started the boil at a room temp. pH of 5.78 exited the boil at pH 5.48. Drop = 0.30 pts.
2) A Wort which started the boil at a room temp. pH of 5.64 exited the boil at pH 5.41. Drop = 0.23 pts.
3) A Wort which started the boil at a room temp. pH of 5.48 exited the boil at pH 5.30. Drop = 0.18 pts.
4) A Wort which started the boil at a room temp. pH of 5.32 exited the boil at pH 5.19. Drop = 0.13 pts.

The Table XI data is said within the text to be sourced from no less than Narziss.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1975.tb03663.x

This equation offers a very good fit to the above data:

pH_Knockout = 1.86336 + (0.62686 * pH_Pre-Boil)

 

[Silver_Is_Money]

Applying the above equation yields projections of:

1) A Wort which starts the boil at a room temp. pH of 5.20 should exit the boil at pH ~5.12. Drop = ~0.08 pts.
2) A Wort which starts the boil at a room temp. pH of 5.10 should exit the boil at pH ~5.06. Drop = ~0.04 pts.
3) A Wort which starts the boil at a room temp. pH of 5.00 should exit the boil at pH ~5.00. Drop = ~0.00 pts.

 

[Silver_Is_Money]

The thing that the above data negates is using conventional mash pH assistant software to target knockout pH via a method that appears rather common.

And this is the reason why:

The common yet failed method which I'm alluding to calls for using said software to calculate two separate acid additions, one for (lets say) 5.4 pH, and another for (lets say) 5.1 pH, then add only the 5.4 pH calculated acid prediction leading into the mash, and then add the "balance" of the addition (which is calculated via subtracting the 5.4 pH prediction from the 5.1 pH prediction) during the boil.

Let's set the scene for a hypothetical example:

Our givens:
5 Kg. of Pilsner malt with DIpH = 5.84 and BC (buffering capacity) = 34, mashed in distilled water (to simplify things)
Our mash target: pH 5.40
Our knockout target: pH 5.10
The mEq/mL acid strength of 88% Lactic Acid at pH 5.4 = 11.451
The mEq/mL acid strength of 88% Lactic Acid at pH 5.1 = 11.141

Our software's presumed method:
Delta pH = mEq/(BC x Kg.)

Calculation #1:
(5.84 - 5.40) = mEq/(34 x 5)
mEq = 74.8
88% Lactic Acid addition required = 74.8/11.451 = 6.53 mL

Calculation #2:
(5.84 - 5.10) = mEq/(34 x 5)
mEq = 125.8
88% Lactic Acid addition required = 125.8/11.141 = 11.29 mL

Grossly Flawed Presumption:
11.29 mL - 6.53 mL = 4.76 mL of 88% Lactic Acid to be added during the boil

Why is this grossly flawed?
Because per 'pH_Knockout = 1.86336 + (0.62686 * pH_Pre-Boil)' the knockout pH for a Wort which is now at pH 5.4 projects to:
pH_Knockout = 1.86336 + (0.62686 * 5.40)
pH_Knockout projection ~= 5.2484

And the 'better bet' for our second acid addition to be added during the boil is therefore (as opposed to the flawed 4.76 mL):
(5.2484 - 5.10) = mEq/(34 x 5)
mEq = 25.23
88% Lactic Acid addition required = 25.23/11.141 = 2.26 mL

 

[Silver_Is_Money]

The reason why the above yields only a "better bet" as to the second acid addition is that BC itself is highly pH specific, and most 'given' BC's are specific to only pH 5.40, and are really not correct or valid for application at pH 5.10. Therefore even the above "better bet" is flawed. And the proof of this is as follows:

One might ask why we can't simply apply a single dose of acid intended to target 5.10 pH at knockout right at the onset of (or even better, pre) the mash, while applying our givens as seen above (for which one of them states BC = 34)?

Let's try it and in the process find out why BC_pH_5.1 is not = 34:

The direct method applies both equations:
pH_Knockout = 1.86336 + (0.62686 * pH_Pre-Boil)
Delta pH = mEq/(BC x Kg.)

Let's go:
pH_Knockout = 1.86336 + (0.62686 * 5.84)
pH_Knockout = 5.524*
*This means that without any acid addition we should exit the boil/cooling steps at a room temperature projection of ~5.5242 pH

(5.5242 - 5.10) = mEq/(34 x 5) [Applying the 5.40 pH BC incorrectly to 5.10 pH as our one-shot-deal target]
mEq = 72.114
88% Lactic Acid addition required = 72.114/11.141 = 6.47 mL

Error, error, error:
That's essentially the same result as for the 6.53 mL of acid calculated above to move us to 5.4 pH during/exiting the mash, and pre boil. It effectively presumes (as has been done for decades) that entering the boil at 5.40 pH means exiting the boil at 5.1 pH (which is the classic [yet flawed] presumption seen everywhere [and even parroted within peer reviewed brewing science from yore] for a drop of 0.30 pH points across the boil). But in the post above we calculated 6.53 mL + 2.26 mL = 8.79 mL overall, and now we are calculating 6.47 mL overall. Clearly something isn't right! Was Narziss all wet when he observed the flaw in the 0.30 fixed pH point drop 'presumption' across the boil?

The primary error lies in our flawed presumption that we can apply a nominal 5.40 pH derived BC to the target case of 5.10 pH!!!

The amazingly simple answer (whereby to make a single pre mash pH acid addition (as opposed to two acid additions which will only give us a 'better bet' at hitting 5.10 pH post boil and cooling, or at knockout) is to derive malt and unmalted grain and adjunct BC's targeting 5.1 pH to begin with. But to date (and in a world that is closed eye focused only upon the magical target of 5.4 pH within the mash) no one (that I'm aware of) has ever done this. Once we have BC's that are valid for direct use at a targeted pH 5.1 at knockout we can reduce this to a one shot deal as to either acid or base pH correction whereby to hit our 5.1 knockout pH target, for the most part ignoring mash pH. And only then can we (tentatively at least. pending verification) use Kolbach's original 3.5 and 7 divisors as intended by Kolbach (I.E., intended for use only at knockout) for Ca++ and Mg++ ions. And in so doing bring closure to what is presently a jumbled mess of incorrect presumptions leading to flawed predictions.

 

[Silver_Is_Money]

Reflecting upon this further, BC is a 'units applied' quantification of a grists ability to resist change in pH. As acid (or base for the case of deep roast and/or caramel/crystal rich grists) is added, the grists ability to resist change in pH is eroded and diminished. This is effectively the same thing as stating that the grists BC itself is eroded and diminished. For the example I've presented above, the grist which exhibits a BC of ~34 mEq/Kg_pH whereby to transition from 5.84 pH to a target of 5.40 pH exhibits a diminished BC of ~26.47 mEq/Kg_pH whereby to transition from 5.84 pH to a targeted 5.10 pH.

I'm beginning to see where BC_Grist (an aggregate of the grists components individual BC's and masses in relation to grist mass overall) is therefore a pH specific variable, as opposed to being a fixed constant. In order to quantify it, one must do so strictly with respect to a specific/desired pH shift, or Delta_pH. If, as the case presently seems to me to be (subject of coarse to correction or validation), extant BC data (scant and unreliable as it is) is intended for a room temperature target of 5.40 pH, then all of such BC's are only reliable forecasting tools when targeting 5.40 pH. If this holds true, then mash pH predicting software going forward will need to step up to an entirely new level of BC complexity.

In fact things may even be worse. It may be that the very reason why no two researchers BC's seem to correlate within any reliable measure of significance (which hearkens to my terming of such data as being not only scant, but unreliable) may reflect upon their choice of pH target, or lack of choice thereof (which clearly occurs when merely adding a fixed mEq quantity of acid or base for all malts/grains/adjuncts, and then letting the pH terminate 'randomly' where it may thereby). As I currently believe most to all of past research into BC quantification has been done in the latter (lack of a critically specified pH target) fashion via the adding of a fixed mEq quantity of titrant, all of such derived data (which may sum to all of it) may be effectively verging upon being if not virtually useless, then highly useless sans for ballpark level precision.

 

[Silver_Is_Money]

Of course BC could also be specific to temperature (in addition to being specific to target pH). It is well known that weak acids are more acidic (they liberate more H+ ions, reflecting highly altered Ka/pKa dissociation "constants") when placed within an environment that is more 'hot'. The presumed case for a decline in BC may thereby to some measure reflect the condition of boil temperature acid efficaciousness (increased dissociation) vs. mash temperature acid efficaciousness (lesser dissociation). Hmmm ????

We mash pH assistant software developers do not likely account for (or perhaps even have a working means whereby to account for) the variability of Ka's/pKa's which software presumes to be constants, such that the books they are sourced from only offer them to us as "constants". An example of this 'gross deficiency' would be reliance upon math models for the various carbonate species and their reflection upon "Total Alkalinity", whereby the charts which map out the math model of the 'species' are only valid at a single temperature, most likely being 20 degrees C. Mash and boil do not take place at anywhere near 20 degrees C., so such math models are inherently flawed, yet used anyway.

 

[Yooper]

[Maybe this should be under Calculator Support, but I suspect it is working as designed, so I'm putting it under Feature Requests.]

I sometimes need to hold back some or all of my salts to the boil, so as not to drop pH too far. And while I understand moving those additions to the kettle do not affect Mash pH, they do affect Boil pH. It would be nice to see what effect that will have when placed in the Sparge/Kettle section.

Also, when placed in the Sparge/Kettle section, the salts do not show any effect on the ion actuals to see if they are meeting the profile targets. So I have to enter them in the Mash section to dial them in, then move them. Certainly, even though they are post mash, they DO affect the flavor perceptions of the beer, which is why I'm adding them in the first place. As it stands currently, entering them in the Sparge/Kettle section gives me no feedback on their addition in any respect whatsoever.

It is as if the Water Calculator is designed only for mashing and completely disregards any later impact. It could be so much more useful otherwise.

In line with this, perhaps separate Sparge/Kettle sections are in order. While I do BIAB and don't sparge, it seems this section is really ignoring the 'Kettle addition' idea despite the name and treating this as just a Sparge addition. I noticed this because putting salts there, I get an error telling me I need a Sparge volume. But these were Kettle, not Sparge additions. The pre-boil volume should be used in that case for the ion concentration calculations. (I think this part is a bug/oversight/assumption, but I'll just keep it here for now. I can certainly start a different thread or report an issue if preferred.)

Having a separate Kettle section would also facilitate Boil pH acid adjustments as discussed in another Feature Request. The Calc would then provide two pH estimates, one for the Mash, and one for the Boil.

The ion summary should be separate for the Mash/Sparge/Kettle as appropriate.

Thanks for the input. I agree that this needs to be done. Once we're finished with the release of the apps, this is on the list to tackle!

 

[Mont Y. Märzen]

The thing that the above data negates is using conventional mash pH assistant software to target knockout pH via a method that appears rather common.

And this is the reason why:

The common yet failed method which I'm alluding to calls for using said software to calculate two separate acid additions, one for (lets say) 5.4 pH, and another for (lets say) 5.1 pH, then add only the 5.4 pH calculated acid prediction leading into the mash, and then add the "balance" of the addition (which is calculated via subtracting the 5.4 pH prediction from the 5.1 pH prediction) during the boil.

Let's set the scene for a hypothetical example:

Our givens:
5 Kg. of Pilsner malt with DIpH = 5.84 and BC (buffering capacity) = 34, mashed in distilled water (to simplify things)
Our mash target: pH 5.40
Our knockout target: pH 5.10
The mEq/mL acid strength of 88% Lactic Acid at pH 5.4 = 11.451
The mEq/mL acid strength of 88% Lactic Acid at pH 5.1 = 11.141

Our software's presumed method:
Delta pH = mEq/(BC x Kg.)

Calculation #1:
(5.84 - 5.40) = mEq/(34 x 5)
mEq = 74.8
88% Lactic Acid addition required = 74.8/11.451 = 6.53 mL

Calculation #2:
(5.84 - 5.10) = mEq/(34 x 5)
mEq = 125.8
88% Lactic Acid addition required = 125.8/11.141 = 11.29 mL

Grossly Flawed Presumption:
11.29 mL - 6.53 mL = 4.76 mL of 88% Lactic Acid to be added during the boil

Why is this grossly flawed?
Because per 'pH_Knockout = 1.86336 + (0.62686 * pH_Pre-Boil)' the knockout pH for a Wort which is now at pH 5.4 projects to:
pH_Knockout = 1.86336 + (0.62686 * 5.40)
pH_Knockout projection ~= 5.2484

And the 'better bet' for our second acid addition to be added during the boil is therefore (as opposed to the flawed 4.76 mL):
(5.2484 - 5.10) = mEq/(34 x 5)
mEq = 25.23
88% Lactic Acid addition required = 25.23/11.141 = 2.26 mL

And that is likely why we grossly overshot our knockout target all the way to 4.8. We simply used two targets and subtracted the difference.

 

[Mont Y. Märzen]

Of course BC could also be specific to temperature (in addition to being specific to target pH). It is well known that weak acids are more acidic (they liberate more H+ ions, reflecting highly altered Ka/pKa dissociation "constants") when placed within an environment that is more 'hot'. The presumed case for a decline in BC may thereby to some measure reflect the condition of boil temperature acid efficaciousness (increased dissociation) vs. mash temperature acid efficaciousness (lesser dissociation). Hmmm ????

We mash pH assistant software developers do not likely account for (or perhaps even have a working means whereby to account for) the variability of Ka's/pKa's which software presumes to be constants, such that the books they are sourced from only offer them to us as "constants". An example of this 'gross deficiency' would be reliance upon math models for the various carbonate species and their reflection upon "Total Alkalinity", whereby the charts which map out the math model of the 'species' are only valid at a single temperature, most likely being 20 degrees C. Mash and boil do not take place at anywhere near 20 degrees C., so such math models are inherently flawed, yet used anyway.

I'm guessing the purpose of the 20℃ reference temps is due to the difficulty in measuring pH at Mash/Boil temps with any reasonably satisfying accuracy. At least at the homebrew level, instruments available to us just aren't designed for doing so, at least not reliably from what I understand.

Sorry for getting back to this thread 3½ years later, but I certainly digest it better now this time around. Thanks for the education! (now, if only someone with the tools, time, and money can do more Science™!)