Mash pH software feedback request

[Silver_Is_Money]

What feedback does your preferred mash pH assistant software give you when you enter the following simple and exclusive mash water and grist parameters:

1) Mash water = 1.00 gallon (or 3.7854 Liters) of completely mineral free mash water
2) Grist = 2.20462 Lbs. (or 1.00 Kg.) of Acid Malt at 2L (or 3.8 EBC) color

List feedback as to:
1) The initial mash pH indicated before adjustment with either baking soda or Ca(OH)2 [calcium hydroxide, pickling lime, or slaked lime]
2) Grams of baking soda required whereby to hit a mash pH of 5.40
3) Grams of Ca(OH)2 required whereby to hit a mash pH of 5.40
4) Software and version or revision used

 

[Silver_Is_Money]

Acid Malt has two components: Base Malt, and Lactic Acid.

Base malt is 'typically' basic (with respect to pH 5.40) to the measure of ~15 mEq/Kg.

A reasonable nominal presumption (derived from Weyermann's long standing claim that 1% Acid Malt moves a typical or standardized Plato Wort downward by 0.1 pH points) is that ~338 mEq's (with respect to pH 5.4) worth of Lactic Acid (typically albeit not exclusively via Sauergut) are sprayed onto each Kg. of combined base malt and Lactic Acid.

When the basic nature of the 'base' malt (with respect to pH 5.4) is netted out we are left with:
338 mEq acid/Kg. - 15 mEq base/Kg. = ~323 mEq/Kg. of 'effective' acidity remaining in Acid Malt (with respect to pH 5.4). (wherein we are using 5.4 pH as our neutral point, since this is the most commonly targeted mash pH)

To neutralize ~323 mEq/Kg. of acid to a pH of 5.40 requires the addition of ~323 mEq of baking soda (or calcium Hydroxide).

If baking soda fully dissociates within an acidic water (Wort) media via the liberation (escape) of CO2 into the atmosphere during the reaction its basic strength (relative to pH 5.4) is 11.9 mEq/gram

323/11.9 = 27.14 grams of baking soda required.

If baking soda does not fully dissociate whereby to fully and completely react with the acid malt, or if one's initial presumption is that the average acid malt is somewhat greater in 'effective' (or net) acid strength (with respect to pH 5.4) than my presumption of ~323 mEq/Kg as used for this example, or if there is any combination of these considerations (among others, such as the presumption of 15 mEq/Kg base for the base malt, or the assumption that baking soda is not 100% pure, or 100% anhydrous), then a value of somewhat greater than 27.14 grams of baking soda is to be expected as the software's output. The somewhat idealistic derived quantity of 27.14 grams may be viewed as setting a sort of "safe" baseline for the baking soda addition requirement whereby to not accidentally drive the pH much beyond/above 5.40.

 

[Silver_Is_Money]

The solubility of CO2 in water at typical mash temperatures is on the order of only about 20-25% of the solubility of CO2 in water at room temperature. So at mash temperatures most of the acid and baking soda reaction induced CO2 escapes, and as it escapes the NaHCO3 that was initially not dissociated rapidly dissociates and reacts with the acid in the water whereby to replace it. Then wash, rinse, and repeat... until a new mash temperature based equilibrium is established. So if dissociation plays a roll in the requirement for additional baking soda demand within the mash, it is far less of a roll than that presumed for 'STP' reaction conditions.

If baking soda dissociation was so abysmally poor as to be on the order of only ~80% at STP, then 25% of the remaining 20% not dissociated (when we transition to mash temperature and leave STP in our wake) would result in only 5% left un-dissociated for the specific case of being at mash temperature, and therefore at mash temperature the degree of dissociation would be on the order of 95%. With the neutralization to pH 5.40 requirement thereby demanding at most on the order of 5% additional baking soda.

1.05 x 27.14 = 28.5 grams required accordingly. This should set the terminus for the upper limit of addition whereby to hit a pH target of 5.40 (presuming 100% pure and anhydrous baking soda).

So now we have established a nominal lower addition limit of 27.14 grams and a nominal upper addition limit of 28.5 grams.

You may now proceed to report the requested findings for your mash pH assistant software of choice.

 

[Bramling Cross]

I ran your recipe through BS3 using both the original BS MPH 3 model and the new BW model.

I chose Weyermann Acidulated malt rather than the generic Acid Malt option. I followed your grist out to the third decimal place yielding 2lb, 3.3oz of Weyermann Acidulated malt and 1gal distilled water.

BS calculated pH .030 w/o salts using the MPH 3 model. 17.65g of baking soda yielded pH 5.39.

Using the BW model, BS calculated an unadjusted pH of -6.34 (yes, minus). 18.3g of baking soda yielded pH 5.39.

I hope that was helpful.

 

[Silver_Is_Money]

I hope that was helpful.

Indeed it was. Thank you kindly.

For many years Weyerman listed the "Congress Mash" deionized water pH of their Acidulated malt as typically falling between 3.3 and 3.6 pH, but now they suddenly (and to me, rather oddly) list it at a much broader 3.3 to 4.5 pH. I can't explain why the sudden change was made by Wyermann, but something should be presumed to be amiss at some level when a deionized water mash results in a pH of 0.030, and -6.34 pH is truly mind boggling.

But at least the baking soda results are well within in the range of acceptability, so a thumbs up commendation is awarded on that critical score.

 

[Bramling Cross]

Ah, I forgot to mention that BS3 does not support (much to my chagrin) slaked lime, so I was unable to run the second part of the experiment.

Edit: And also, thank you for the kind words!

 

[Silver_Is_Money]

For Mash Made Easy the results are:

1) pH = 3.62
2) 27.14 grams of baking soda
3) 16.75 grams of Calcium Hydroxide
4) Version 10.00

 

[Silver_Is_Money]

Since we know that at a pH of 5.40 a typical Kg. of Acid Malt has ~323 mEq's of 'effective' acidity, and we know that 1 mL of 88% Lactic Acid has 11.451 mEq's of acidity at a pH of 5.40, we can loosely conclude that 1 Kg. of an average or nominal Acid Malt should be the acid equivalent of roughly 28.21 mL of 88% Lactic Acid, since 323 mEq/11.451 mEq/mL= 28.21 mL.

If we therefore added 28.21 mL of 88% Lactic Acid to 1 gallon of DI water, what would we estimate the resulting pH to be?

Givens:
The Ka dissociation constant of Lactic Acid is listed as being: 1.38 x 10^-4
28.21 mL of 88% Lactic Acid in 3.7854 Liters of water has a molar concentration of 0.087124 as Lactic Acid.

Therefore:
[H3O+] = SQRT( 1.38 * 10^-4 * 0.0871)
[H3O+] = 0.003467
-Log(0.003467) = 2.46

We would on first presumption thereby expect the resulting pH to be within the "loose" ballpark vicinity of 2.46.

But we also know that Acid Malt is roughly 97% Pilsner base malt and 3% Lactic Acid, and a typical DI water mash pH for a Pilsner base malt when standing alone is in the ballpark of ~5.82.

We also know that a pH is an exponent within a log base 10 system. And we know that both lactic acid and Pilsner base malt have buffering coefficients that are fully independent of each other, making the solution to this problem rather complex. Mash Made Easy solves this mystery to a pHDI of 3.62 for acid malt as seen in post #7 above (albeit that it begins with 3.62, but if you reverse solve the subsequent math it resolves to 3.62 for the case of DI water [and to different pH values for variations of mineralized water]).

But we should all be capable of seeing that if we take a mixture of 28.21 mL of 88% lactic acid in 1 gallon of DI water at loose ballpark estimate of 2.46 pH and add to it nearly 1Kg. of Pilsner base malt that will ballpark DI water mash at 5.82 pH, it should be easy to perceive as to how and why Weyermann generally estimates the DI mash pH for their Acid Malt to be within a ballpark of ~3.3 to ~3.6 pH.

 

[Silver_Is_Money]

A bit of bonus trivia whereby to link a Ka dissociation constant to a pKa dissociation constant.

When we look them up we find that for Lactic Acid these constants are given as:
Ka = 1.38 x 10^-4
pKa = 3.86

1.38 x 10 ^-4 = 0.000138
-Log(0.000138) = 3.86

10^-3.86 = 0.000138 = 1.38 x 10^-4

So just as for "pH" (or p[H3O+] ) being a log base 10 exponent, the same relationship holds true for pKa being an exponent that is log base 10.

 

[Silver_Is_Money]

I now return you to performing the requested post #1 tests for your mash pH assistant software of choice.

 

[Silver_Is_Money]

This link attached chart indicates that the pH of a 100 mmole/L solution of Lactic Acid in water is 2.44.

The strength of a solution of 28.21 mL of 88% Lactic Acid in 1 Gallon of water is slightly weaker at 87.124 mmole/L, so this lends credence to my calculated pH for it (as seen above) being 2.46.

https://www.aqion.de/site/ph-of-common-acids
It also lends a level of eye raising mistrust to software exhibiting pH's of 0.030 and -6.24, and particularly more so as for these the basic "base malt" (which elevates pH) is already present.

(Note: "base malt" is not named as such because it is basic with respect to pH 5.4. It is so named because it typically provides the base, or bedrock, or foundation for a grist. This can unfortunately lead to a level of confusion as to the use of base/basic terminology.)

 

[Silver_Is_Money]

For Brewers Friend I get the following:

1) pH = 3.35
2) 29.3 grams of baking soda
3) 16.28 grams of Calcium Hydroxide
4) Current version (as of today)

 

[Silver_Is_Money]

Another minor sidetrack: An easy ratio relationship that we can eek out is that 1.25 ounces of acid malt is the 'nominal' acid equivalent of 1 mL of 88% Lactic Acid at pH 5.40.

1 Kg. = 2.20462 Lbs.

2.20462 Lbs. x 16 Oz./Lb. = 35.27392 ounces of Acid Malt

35.27392 Oz. per Kg. / 28.21 mL 88% Lactic Acid* per Kg. = 1.25 Oz. Acid Malt to 1 mL of 88% Lactic Acid
(Where * = effective, or net)

 

[Silver_Is_Money]

As water volume is doubled for the case of a mildly acidic yet otherwise non-buffered (with respect to our target pH of 5.4) system we would expect pH to rise by ~0.30 points per each volume doubling, and by a full 1.00 pH points for a ten-fold volume increase. This sets the upper limit case for pH rise as volume increases. But for highly buffered systems such as a mashing grist we would hardly expect the pH to vary much if at all (as detectable via our generally budget class pH meters, at least) with mash water volume doubling (due to the strong buffering effect and impact of the malts).

Try DI water mashing your favorite recipe (by simply zeroing out all mineralization) within your favorite software, and then for grins double the mash water volume and observe what happens to the mash pH. Due to the relatively strong grist buffering it shouldn't move much if at all when doubled. You are welcome to post your findings for this twist here as well. Then try halving the mash water. Then halve it again.... Observe whether or not the strong grist buffering resists pH shift.

 

[Silver_Is_Money]

With respect to the above, and for an otherwise non-buffered system at pH 5.4:

[H3O+] ion molar concentration = 10^-5.4 = 0.000003981

When we double the waters volume the concentration of [H3O+] ions is now cut in half.

[H3O+]/2 = 0.000003981/2 = 0.000001991

And what pH is now expected due to our volume doubling?

-log(0.000001991) = 5.70102 (in this you see the ~0.3 pH point shift mentioned in my post above)

And if instead we halved the water volume the concentration of [H3O+] ions would double:

2 x 0.000003981 = 0.000007962

And the resulting pH would be:

-log(0.000007962) = 5.09897 pH (again verifying our presumption of a roughly 0.3 pH shift)

 

[Silver_Is_Money]

The same ~0.30 pH point shift for volume doubling or halving holds true for all pH's. This special non-buffered case sets the extreme limit for pH shift movement due to doubling or halving the volume of water.

But again I must emphasize that a mashing grist creates a highly buffering Wort system. The greater the buffering, the greater the resistance to change in pH.

 

[Silver_Is_Money]

What might be the theoretical pH of pure (straight up, uncut, undiluted) 88% Lactic Acid?

For the case of full dissociation, pH is the negative log of molarity for the case of a monoprotic acid, and 88% Lactic Acid is ~11.78 molar, so the anticipated or theoretical pH of straight up 88% Lactic Acid is on the order of:

-log(11.78) = -1.07115 pH

But since concentrated Lactic Acid, being in the class of weak acids, is not likely to be fully dissociated, its actual pH will likely prove to be something greater (as in less acidic) than -1.07115.

 

[Silver_Is_Money]

If your preferred mash pH assistant software will not permit you to set up a mash with 1Kg. of Acid Malt added into 1 gallon (3.7854 Liters) of mineral free water, whereby to fully participate in this test, you should be able to substitute the following additions whereby to proceed (whereby you are effectively creating ~1Kg. of Acid malt "on the fly"). Please indicate within the results if this substitution was made:

0.97 Kg. Pilsner Malt (2.1385 Lbs.) [~15 mEq's of base with respect to pH 5.4]
29.5 mL of 88% Lactic Acid [~338 mEq's of acid with respect to pH 5.4]
Net (or effective) acidity =~323 mEq's

 

[Silver_Is_Money]

In several of AJ deLange's posts to this forum he indicated that when he performed an actual Congress Mash of Weyermann acidulated malt his observed pHDI for his particular tested lot was 3.62. I'm quite certain that this was my source for selecting 3.62 pHDI.

 

[Silver_Is_Money]

So far results have only been presented for:

BS3
Mash Made Easy V_10.00
Brewers Friend

Still waiting on the observed results for at least a handful of other mash pH assistant software packages.

And for bonus points, tell us how it handles pH with respect to mineral free water volume changes (I.E., a couple of volume doublings and halvings).

 

[Silver_Is_Money]

For EZ Water, with 2.1385 pounds of Pilsner malt mashing in 1 gallon of mineral free distilled water to which 29.5 mL of 88% lactic acid has been added, I get the following:

Pre Baking Soda or Slaked Lime addition pH = -5.90 (minus 5.90)
56.5 g. Baking Soda required to hit pH 5.40
34.8 g. Slaked Lime required to hit pH 5.40

These additions seem to be off on the high side by about a factor of 2. Perhaps I'm doing something wrong?

 

[Silver_Is_Money]

Results for MpH versions 3.0 and 4.2, using 2.1385 Lbs. of base malt and 29.5 mL of 88% Lactic Acid, and 1 gallon of mineral free distilled water:

1) pH =-2.67 (minus 2.67)
2) 28.05 grams of baking soda
3) 19.25 grams of Calcium Hydroxide
4) Version 3.0
Comments: Result varies somewhat depending upon the base malt Lovibond color value entered.


1) pH =-11.51 (minus 11.51)
2) Unsolvable for NaHCO3 (pH first went up as grams added increased, then went back down again)
3) 19.55 grams of Calcium Hydroxide
4) Version 4.2
Comments:
Result varies somewhat with regard to which Pilsner base malt is selected, as is to be expected.
Perhaps I'm doing something wrong, particularly due to the strange baking soda output. ???

 

[marc1]

What feedback does your preferred mash pH assistant software give you when you enter the following simple and exclusive mash water and grist parameters:

1) Mash water = 1.00 gallon (or 3.7854 Liters) of completely mineral free mash water
2) Grist = 2.20462 Lbs. (or 1.00 Kg.) of Acid Malt at 2L (or 3.8 EBC) color

List feedback as to:
1) The initial mash pH indicated before adjustment with either baking soda or Ca(OH)2 [calcium hydroxide, pickling lime, or slaked lime]
2) Grams of baking soda required whereby to hit a mash pH of 5.40
3) Grams of Ca(OH)2 required whereby to hit a mash pH of 5.40
4) Software and version or revision used

I haven't used Bru'n Water for beer for a while, but I had downloaded a recent version earlier this year.

I plugged this excercise in:

1) The initial mash pH indicated before adjustment with either baking soda or Ca(OH)2 [calcium hydroxide, pickling lime, or slaked lime] - 0.10
2) Grams of baking soda required whereby to hit a mash pH of 5.40 - No amount of baking soda that I entered had any effect on the mash pH, it stayed at 0.10, even at 1,000,000 g/gallon
3) Grams of Ca(OH)2 required whereby to hit a mash pH of 5.40 - 8.65
4) Software and version or revision used BrunWater1.25

 

[Silver_Is_Money]

I haven't used Bru'n Water for beer for a while, but I had downloaded a recent version earlier this year.

I plugged this excercise in:

1) The initial mash pH indicated before adjustment with either baking soda or Ca(OH)2 [calcium hydroxide, pickling lime, or slaked lime] - 0.10
2) Grams of baking soda required whereby to hit a mash pH of 5.40 - No amount of baking soda that I entered had any effect on the mash pH, it stayed at 0.10, even at 1,000,000 g/gallon
3) Grams of Ca(OH)2 required whereby to hit a mash pH of 5.40 - 8.65
4) Software and version or revision used BrunWater1.25

I just tried this in the free version 1.25, and it was as you found, sans that for me the Ca(OH)2 calcium hydroxide required to hit pH 5.40 was 11.66 grams. Baking Soda failed to move the pH from the initial value of 0.10 at any added quantity.

 

[Silver_Is_Money]

I did some quick ciphering, and 11.66 grams of Ca(OH)2 is correct for the case of 2 x OH- ions per Ca(OH)2 molecule, but only if the Ca++ calcium ion is completely missing in action, and thereby is not simultaneously lowering the mash pH while the OH- ions are raising it.

 

[marc1]

I just tried this in the free version 1.25, and it was as you found, sans that for me the Ca(OH)2 calcium hydroxide required to hit pH 5.40 was 11.66 grams. Baking Soda failed to move the pH from the initial value of 0.10 at any added quantity.

I checked it out again, I think the reason we got different results is that you inadvertently used the cell for CaCO3 instead of Ca(OH)2

 

[Silver_Is_Money]

I checked it out again, I think the reason we got different results is that you inadvertently used the cell for CaCO3 instead of Ca(OH)2

Indeed you are correct sir. The extremely low result of 8.65 grams Ca(OH)2 is also what I'm now seeing. I was using CaCO3 inadvertently as my entry cell just as you surmised. I'm chalking it up to age. Thank you for correcting me.

When you halve the Ca(OH)2 amount value to 4.325 grams and then double the distilled mash water volume to 2 gallons (whereby to maintain the Ca(OH)2 addition at the very same 8.65 grams) does the resulting mash pH oddly jump from 5.40 pH to to 10.10 pH? That's some seriously strange distilled water. Seriously not neutral as would be expected for water having zero mineral ions. Its nigh-on as if the mineral free water that should be seen as essentially a non-participant has more power to raise mash pH than does the Ca(OH)2 itself.

From post #15 above we know that doubling the water in an unbuffered system will only raise the pH 0.3 points. But we also know that due to the ~970 grams of base malt in 1 Kg. of Acid Malt this is a well buffered system. And buffers (by definition) resist change in pH. Fighting against buffering is like puling on a rope that has someone ultimately a tad weaker than you pulling on the other side, as opposed to pulling on a rope that has no one pulling on the other side.