Large discrepancy between BrunWater and MME on high % adjunct beer

[dperrigan]

Hi all. I've been using both BrunWater (1.25) and Mash Made Easy (10.30) for quite some time now. For any given recipe so far they've come in within 0.1 pH of each other. The measured pH of my mash about 50 minutes in is usually right at the average between the two predictions. In other words, I both love and depend on these two spreadsheets.

This weekend's beer will be a Belgian Wit. The mashbill is 50% Pilsner, 33% Flaked Wheat, 10% Red Wheat Malt, 5% Flaked Oats, and 2% Carapils. After my usual addition of small amounts of gypsum, Calcium Chloride, and Epsom I got predictions of 5.39 from BrunWater and 5.84 from MME. I've never seen that much of a difference between the two before. I'm assuming it is the high percentage of flaked grains causing the problem.

Has anyone else run into this? Would the flaked grains cause that much higher of a pH?

Thanks,
Dan

 

[TheMadKing]

Announcing the release of 'Mash Made Easy' version 10.70, including the new 'Knockout pH' module

This might help. I just had the same issue this past week

and short answer yes because MME uses the DI pH of specific grains. The DI pH of your wheat is 6.1 which drives up your pH substantially in something like a wit. I found it to be very accurate

 

[VikeMan]

This weekend's beer will be a Belgian Wit. The mashbill is 50% Pilsner, 33% Flaked Wheat, 10% Red Wheat Malt, 5% Flaked Oats, and 2% Carapils. After my usual addition of small amounts of gypsum, Calcium Chloride, and Epsom I got predictions of 5.39 from BrunWater and 5.84 from MME. I've never seen that much of a difference between the two before. I'm assuming it is the high percentage of flaked grains causing the problem.

If you post the actual grain amounts, your starting water profile, volume of strike water, and salt additions, I can give you a third opinion. Also, what pilsner malt are you using?

 

[dperrigan]

Hi VikeMan. 4.35lbs Avangard Pilsner, 2.87lbs Briess Flaked Wheat, 0.87lbs Briess Red Wheat, 0.44lbs Briess Flaked Oats, 0.17lbs Carapils. Starting with 6.85 gallons of distilled water. Adding 2.1g Gypsum, 2.7g Calcium Chloride, 2.7g Epsom Salt.

Thanks!

 

[VikeMan]

Hi VikeMan. 4.35lbs Avangard Pilsner, 2.87lbs Briess Flaked Wheat, 0.87lbs Briess Red Wheat, 0.44lbs Briess Flaked Oats, 0.17lbs Carapils. Starting with 6.85 gallons of distilled water. Adding 2.1g Gypsum, 2.7g Calcium Chloride, 2.7g Epsom Salt.

BrewCipher (which uses the MpH 4.2 model) predicts a mash pH of 5.64 with the above.

 

[dperrigan]

Thanks. So the flaked wheat and oats ARE pushing the pH up.

 

[VikeMan]

Thanks. So the flaked wheat and oats ARE pushing the pH up.

Flaked Wheat and Flaked Oats (and Wheat Malts, for that matter) don't contribute as much acidity as Pilsner Malts.
Note that the prediction of 5.64 I provided is with the MpH 4.2 model embedded in BrewCipher. I haven't looked at BrunWater for a long time, so I can't say what it's doing.

 

[Silver_Is_Money]

To add to what was stated by @TheMadKing, mash pH prediction requires not only that DI water mash pH valuations be presumed for all constituents, but that buffering capacity valuations presumptions be made for all constituents as well.

MME allows for its presumptions for both pHDI and BC to be overridden by actual measured valuations.

 

[Silver_Is_Money]

Here is how the current Mash Made Easy (MME) version 10.85 sees it:



Calling for the addition of 5 mL of 88% Lactic Acid whereby to hit a ballpark of 5.40 pH.

 

[Silver_Is_Money]

Note that all components involved lead to a final mEq of 57.17.
The mEq/mL acid strength of 88% Lactic Acid at the targeted pH of 5.40 is 11.451 mEq/mL

Therefore: 57.17 mEq ÷ 11.451 mEq/mL = 4.993 mL of 88% Lactic Acid

This is not to say that your local reality will be 5 mL of 88% Lactic Acid leading to a nominal mash pH (for a sample taken at least 30 or more minutes into the mash, and measured at room temperature with no pH probe stirring, and after about a minute sitting in the sample for probe stability) will be 5.40 pH, but rather that the presumptions inherent within MME version 10.85 see it this way.

 

[Silver_Is_Money]

See here for something of relevance which I entered into a forum thread a bit earlier this morning:

https://www.homebrewtalk.com/threads/water-co-doesnt-report-hc03.694778/post-9153714

 

[Silver_Is_Money]

Another reason why MME may be predicting a higher mash pH is that MME is unique in not applying Kolbach's mash pH suppression as induced by calcium and magnesium ions within ones water "fully" to the mash, as is done for the other of various softwares. AJ deLange recognized years ago that Kolbach's work upon the downward pH shift induced by Ca++ and Mg++ was measured by Kolbach at Knockout (I.E., post boil and cooling), and not during the mash at all. AJ directly observed and measured ~50%-60% of the Kolbach measured downward pressure upon pH during the Mash proper. Then chemists Barth and Zaman went even further than did AJ in utterly destroying the "full" application of Kolbach's math model to the mash proper. Other softwares seriously need to catch up in this regard.

Also, another reason: Other softwares presume that 100% of grist component acidity is released within the mash water, whereas MME factors in the users degree of grist pulverization so as to critically modify this aspect, just as is logically done for predicting ones estimate of OG yield vs. the pulverized yield ideal, as a consequence primarily of ones degree of mill gap crush. Only a fully pulverized grist (as for a Congress Mash, as used in strictly a lab setting) can liberate every degree of everything that is initially locked within the various (and various forms of) grain kernels. Other softwares need to catch up here as well. They all presume your mill gap crush to be at the level of pulverization for the purpose of mash pH prediction.

 

[dperrigan]

Thanks, guys.