Yet another Bru'n Water vs thread. Please help - results dramatic

[Rev2010]

I've inputted my water report and a recipe with some water treatments into Brewer's Friend and it tells me to add 2ml lactic acid (88%) to reach a pH of 5.4. The same info inputted into Bru'n Water tells me without any acid my pH is estimated to be 4.97 and I need to add alkalinity. Info below, please tell me which to trust.

Water report:

Calcium: 7.3
Magnesium: 1.7 mg/l
Sodium: 12 mg/l
Chloride: 18 mg/l
Sulfate: 5.1 mg/l
Alkalinity as Alkalinity: 19.2 ppm as CaCO3
pH: 7.4

Water additions:

Gypsum: 0.5 g/gal
Calcium Chloride: 0.5 g/gal
Baking Soda: 0.2 g/gal

Mash water: 5.5 gallons
Sparge water: 3.25 gallons

Grist info:

13lbs 2-row 1.8L
1lb Munich malt 10L
1lb Caramel 60 60L
1lb Chocolate malt 350L
.75lb Debittered black malt 550L

 

[ajdelange]

I wouldn't believe either of them. I put your numbers into a robust spreadsheet which tells me that if the 2 row is Munton's Maris Otter you would need 7.3 mL of lactic acid whereas if you used M.O. from Crisp you would need 3.2 and if you used Rahr pale ale malt, 3.7 mL. Without any acid the expected pH range would be 5.49 -5.61. It's not likely that you would need any alkali. Note that eliminating the NaHCO3 addition the acid requirement for the Munton's MO goes down to 6.29 mL and the requirement for Crisp's to 2.16 mL.

Now the numbers I come up with are based on my picking malts that I think may be like yours. The numbers I gave are obviously very dependent on which malt I pick. This is why you should not trust any program to predict mash pH for you. Measure it by mashing about a pound of grain with your treated water.

 

[Rev2010]

Now the numbers I come up with are based on my picking malts that I think may be like yours. The numbers I gave are obviously very dependent on which malt I pick. This is why you should not trust any program to predict mash pH for you. Measure it by mashing about a pound of grain with your treated water.

The 2-row is regular Briess 2-row, the Munich is Briess Boonlander, and the Caramel is Briess as well. I haven't yet picked up a pH meter again since I restarted my brewing in my new apartment. I stopped using my pH meter after about 20 brews or so cause I was finding my measurements at the time were nearly spot on to the predictions in Brewer's Friend. But I got curious to check and was surprised when Bru'n Water came up with a pH below 5 with zero lactic added. Definitely have to pickup a meter soon to at least get a ballpark reading over a number of batches. Thanks for your input AJ! Much appreciated.


Rev.

 

[Silver_Is_Money]

If this helps somewhat: Per Briess data, the DI pH of their 2-Row Brewers malt is about 5.57, the DI pH of their 10L Bonlander is about 5.50, and the DI pH of their 10L crystal is about 5.12. The 60L Caramel is about 4.75 DI_pH. The 350L Chocolate is about 4.7 DI_pH. I don't know what the typical DI_pH for debittered black 550L is, but I would guess perhaps 4.5 to 4.6 pH.

 

[Rev2010]

So I didn't add any lactic acid for yesterday's brew and bought a pH meter in the interim and tested yesterday. Mash ph was 5.05. So Bru'n Water was apparently the most accurate for this estimate. Glad I didn't follow the other calcs and add lactic acid as they were recommending.


Rev.

 

[Silver_Is_Money]

Might I ask if you waited until at least 30 minutes into the mash to pull your pH sample, and if you fully cooled it to room temperature (68 degrees F.) before reading it?

Also, did you take a follow-up mash pH reading at the 60 minute mark.

Repeatedly now, I'm seeing reports showing that an initially low mash pH reading rises by as much as 0.2 to 0.3 points by the end of a 60 minute mash.

 

[Silver_Is_Money]

I'm beginning to speculate that perhaps the very high acidity of the darkest malts within the grist is fully released quite early in the mash, and the essentially basic (disclaimer: this specifically with respect to the chosen mash pH target) and thereby much lower base malt acidity (which is inherently of a pH greater than the chosen mash pH target, thus my carefully worded proclamation of "basic") is progressively released only later in the mash, continuing in this release to some extent right up to the 60 minute mark.

The above would explain why those who take multiple pH readings throughout the progression of a mash which contains dark roasted grist components are often seeing a rise in mash pH over the duration of the mash. It would also explain why many people recommend that the very most "basic" representatives among the base malts, I.E., the Pilsner malts, be preferentially mashed for 90 minutes rather than the more typical 60 minutes.

Edited only to fix a typo.

 

[Silver_Is_Money]

I'm quite confident that this will drive A.J. (and likely also D.M Riffe) to derision, but this is a simple base 10 logarithmic method for determining overall mash pH which is from a mash pH math model which I dreamed up and then completely abandoned awhile back, but which I may need to revisit and reconsider if low mash pH's for recipes such as stouts and porters continue to be observed. The individual grist components best initial guess as to their individual DI_pH values are seen here as the exponents within each grist equation.

13lbs 2-row 1.8L .......................... 10^-5.57 * 13 = 0.00003499
1lb Munich malt 10L ...................... 10^-5.50 * 1 = 0.000003162
1lb Caramel 60 60L ....................... 10^-4.75 *1 = 0.000017783
1lb Chocolate malt 350L ................. 10^-4.70 *1 = 0.000019953
.75lb Debittered black malt 550L ..... 10^-4.55 *0.75 = 0.000021138

Sum of all grist values from above = 0.000097026
0.000097026/16.75 lbs. grist = 0.000005793
-log(0.000005793) = 5.24 pH

This simple method (which admittedly ignores the impact of buffering, which can be added for refinement **) predicts a mash pH of 5.24 at the conclusion of 60 minutes of mashing for your grist. If you measured 5 as the pH early on, and it rose 0.2 to 0.3 pH over the course of 60 minutes, this (5.24) would be a reasonable approximation of what might have been seen at the end of the mash with respect to pH.

** When the downward shift in pH due to your added minerals is applied to each of the above DI_pH's, and the lower mineral induced pH is used instead of the DI_pH as the "exponent" for each individual grist component, the mash pH prediction is accordingly lower, and edges closer to your actual observation.

 

[Rev2010]

Might I ask if you waited until at least 30 minutes into the mash to pull your pH sample, and if you fully cooled it to room temperature (68 degrees F.) before reading it?

I took the sample at the 30 minute mark and cooled it down to 80 degrees before taking the reading. Two point calibrated the meter before use.


Rev.

 

[Silver_Is_Money]

I took the sample at the 30 minute mark and cooled it down to 80 degrees before taking the reading. Two point calibrated the meter before use.

Was the meter calibrated using 80 degree F. calibrants?

 

[Rev2010]

Was the meter calibrated using 80 degree F. calibrants?

The solutions were at about 74 degrees. The meter has ATC.


Rev.

 

[Silver_Is_Money]

ATC does not correct pH for temperature. ATC only corrects the meters response time with respect to sample temperature. And since meters "time out" and tell you the pH they are experiencing at the time when they time out, and the "time out" time span is related to temperature, the meter must allow for greater or lesser time spent reading the sample before it times out and reveals to you its quote-unquote stable pH findings.

 

[Rev2010]

ATC does not correct pH for temperature. ATC only corrects the meters response time with respect to sample temperature. And since meters "time out" and tell you the pH they are experiencing at the time when they time out, and the "time out" time span is related to temperature, the meter must allow for greater or lesser time spent reading the sample before it times out and reveals to you its quote-unquote stable pH findings.

My meter displays a smiley face once it's stabilized the reading, it's an Apera meter. And 6 degrees difference between calibration solution temperature and sample temperature I can't believe would have any discernible affect on the reading.


Rev.

 

[Silver_Is_Money]

The error is on the order of 0.003 pH/ºC/pH unit (where pH unit is how far away from pH 7 the sample you are reading is).

Lets say you are 2 units from pH 7 (since reading pH's in the 5's), and 3.33 degrees C off in temperature. That would result in:

Error = 3.33 x 0.003 x 2 ~= 0.02 pH points.

 

[Silver_Is_Money]

Via the application of the above ballpark formula, readings taken at mash pH temps would be off (vs. room temp) by about 0.27 to 0.31 points to the low side (mash temperature dependent). But at the same time they would be correct. Welcome to the world of pH.

 

[ajdelange]

13lbs 2-row 1.8L .......................... 10^-5.57 * 13 = 0.00003499
1lb Munich malt 10L ...................... 10^-5.50 * 1 = 0.000003162
1lb Caramel 60 60L ....................... 10^-4.75 *1 = 0.000017783
1lb Chocolate malt 350L ................. 10^-4.70 *1 = 0.000019953
.75lb Debittered black malt 550L ..... 10^-4.55 *0.75 = 0.000021138

Sum of all grist values from above = 0.000097026
0.000097026/16.75 lbs. grist = 0.000005793
-log(0.000005793) = 5.24 pH

This simple method (which admittedly ignores the impact of buffering, which can be added for refinement/

Buffering isn't a refinement. Buffering is the key to the chemistry. Until you understand and can apply that concept you will never be able to come up with anything other than algorithms which appear to work some times.

Here's of those. Just take the weighted averages of the pH's. For this case that's 5.42. If you had grists with the given DI pH's and all had buffering of -40 then the mash pH would be 5.36. The weighted average pH estimate is only 0.06 from 5.42 and closer that the weighted hydrogen ion concentration. Thus it's a better guess.

 

[ajdelange]

ATC does not correct pH for temperature. ATC only corrects the meters response time with respect to sample temperature. And since meters "time out" and tell you the pH they are experiencing at the time when they time out, and the "time out" time span is related to temperature, the meter must allow for greater or lesser time spent reading the sample before it times out and reveals to you its quote-unquote stable pH findings.

ATC has nothing to do with time. It compensates for the response (mV/pH) of the electrode as a function of temperature. pH meter calibration depends on knowing the electrode's slope and offset. ATC adjusts the slope (mV/pH) to the proper value at sample temperature relative to the slope measured at the calibration temperature by the factor (Tsamp/Tcal) where the temperatures are in Kelvins. This is all explained in the Sticky on pH meter calibration.

 

[Silver_Is_Money]

Here's of those. Just take the weighted averages of the pH's. For this case that's 5.42. If you had grists with the given DI pH's and all had buffering of -40 then the mash pH would be 5.36. The weighted average pH estimate is only 0.06 from 5.42 and closer that the weighted hydrogen ion concentration. Thus it's a better guess.

The OP measured 5.05 pH during his mash, and as a consequence a prediction of 5.36 pH is to be seen as superior to a prediction of 5.24 pH. These sort of low mash pH measurements for beers with noticeable quantities of deep roasted components appear to be slowly piling up. And that is why I brought up an abandoned model. How long can we continue to blame pH meters and their operators for false low pH readings? Where are those who are actually measuring noticeably higher pH readings for the likes of Stouts and Porters? I wish they would begin to speak up.

 

[ajdelange]

The OP measured 5.05 pH during his mash,

OP may have measured 5.05 but the pH certainly wasn't 5.05. The actual mash pH was probably about 5.4 without addition of acids or bases. Use common sense. 83% of the grist has DI pH greater than 5.05. The proton deficit of the base malt is over 200 mEq at pH 5.05. The three dark malts have deficits of about -30 mEq to that same pH. Where would the extra acid equivalent to almost 5 mL of concentrated sulfuric acid come from?

and as a consequence a prediction of 5.36 pH is to be seen as superior to a prediction of 5.24 pH.

Well that's what I said (but I don't think that's what you meant to say). In any case you have missed the point. I was trying to illustrate that there are lots of ways to jumble up the numbers and come up with pH estimates that may match in some cases but not in others. That's the nature of empirical stabs at things. Sometime they work but when they don't one has little recourse but to stuff in 'adjustment factors' and that's what I have been watching Gen I calculator authors do for years. Let me note that I am not against empiricism per se. It has been, when we didn't have the tools for exploration we have available to us today, our saviour in many disciplines. In this particular application, however, there is no base of observations to show that the weighted mean of the hydrogen ion concentrations or the weighted mean of the logs of the hydrogen ion concentrations correlates with estimated mash pH to any reasonable degree of significance nor is there any tie in with the science that gives us any reason to believe that there would be.

[Edit]Actually the logs of hydrogen ion concentration (pH) weighted by the products of the malt's mass and its linear buffering coefficient do lead to a valid prediction of mash pH. See No. 21.

These sort of low mash pH measurements for beers with noticeable quantities of deep roasted components appear to be slowly piling up.

They do?

How long can we continue to blame pH meters and their operators for false low pH readings?

As long as they continue to use their pH meters improperly which clearly many if not most do. Forgive me for pointing the finger at you but No. 12 here represents a total misunderstanding as to how a pH meter, and in particular, ATC, functions. You are by no means alone. I was once asked a question representative of a similar level of misunderstanding of ATC but this time it was by the QC lab manager of a rather prominent supplier to both the craft and homebrewing communities.

As I have said here many times before the pH meter is an instrument and as is the case with many instruments its proper use is an art. As is the case in general in life it takes some time to acquire that art. I believe I have aquired it. Were I to observe a pH of 5.05 in a mash of OP's composition my first move would be to do a cal check on the meter. If one makes many pH measurements and educates himself somewhat as to how a pH meter works (see Sticky on calibration in this forum for a starter) he will eventually acquire the art and will know right away when a reading is funny.

Where are those who are actually measuring noticeably higher pH readings for the likes of Stouts and Porters? I wish they would begin to speak up.

I'm speaking. All my stouts came in at pH around 5.5 (they were the standard 80/10/10 recipe or very close to it).

I have never, in a stout or any other kind of beer, seen a stable pH reading of 5.05. Note that I said stable because if you do a mash with added acid or sauermalz the meter will read the pH of the liquid which is initially low because of the acid but as the liquid penetrates the grist and reacts the pH rises.

 

[Silver_Is_Money]

Buffering isn't a refinement. Buffering is the key to the chemistry. Until you understand and can apply that concept you will never be able to come up with anything other than algorithms which appear to work some times.

Here's of those. Just take the weighted averages of the pH's. For this case that's 5.42. If you had grists with the given DI pH's and all had buffering of -40 then the mash pH would be 5.36. The weighted average pH estimate is only 0.06 from 5.42 and closer that the weighted hydrogen ion concentration. Thus it's a better guess.

Obviously I should have applied the word "must" where I used the word "can". I simply left the buffered exponent value calculations aside in order to simplify this for the readers.

Since 10^-pH = moles of acid (hydrogen ion concentration) in solution, I'm at a loss as to why summing up the individual grist components quantifiable moles of acid and then via negative log reconverting them back to an "overall" wort pH is to be considered a highly invalid approach. pH itself is a logarithmic scale. Why then is it wrong to apply logs (exponents) to the solution and instead go with what is essentially a linearized solution?

 

[ajdelange]

Since 10^-pH = moles of acid (hydrogen ion concentration) in solution, I'm at a loss as to why summing up the individual grist components quantifiable moles of acid and then via negative log reconverting them back to an "overall" wort pH is to be considered a highly invalid approach.

Because it in no way represents the chemistry. If you put a mole of hydrochloric acid into a liter of water it completely dissociates and so there will be a mole of H+ (ions though the pH will be around -10). If you now add a mole of lye (NaOH) it will absorb all those protons, the hydrogen ion concentration will drop to 1E-7 and the pH will be 7. Using your scheme we would have (36*1 + 40*0)/76 = 0.473684 (36 is the grams per mole of HCl and 40 the grams per mole for NaOH) for your estimated hydrogen ion concentration and consequently -log(36/76) = 0.32 for your pH estimate. The actual pH would be 7. The pH of a solution of 40 grams of NaOH in a gallon of water is about -14. Thus the weighted pH average is (-36*10 + 40*14)/76 = 2.63 which is, while not quite so ridiculous, is almost equally so.

If you dissolve 192.12 grams (1 mole) of citric acid in 5 gallons of water the pH will be 2.23 (the DI pH). If you now add 100 grams of lye the pH will be 6.42. Your method would give us (192.12*10^-2.23 + 100*10^-14)/292.12 = 0.00387268 for the H+ ion concentration and -log((192.12*10^-2.23 + 100*10^-14)/292.12) =2.41

So we have seen that your method does not work with strong acid and strong base nor with weak acid and strong base. Why would we expect it to work with weak acids and bases (which is what malts are or, rather, a mix of weak acids/bases)? So let's put a mole of citric acid and a mole of succinic acid in 5 gal of DI water. As we have seen the DI pH for the citric acid is 2.2280. For the succinic acid it is 2.7454. The molecular weight of succinic acid is 118.09 g. You would estimate the pH of the mix as
•print -log((118.09*10^-2.7454 + 192.12*10^-2.2280)/(118.09 + 192.12))
2.36173
But the weighted averages of the pH's is
•print (118.09*2.7454 + 192.12*2.2280)/(118.09 + 192.12)
2.42496
And the weighted harmonic average is
•print 1/( (118.09/2.7454 + 192.12/2.2280)/(118.09 + 192.12))
2.4002
As the actual answer for such a mix is 2.2074 all these answers are wrong. But why are they closer in this case than in the other examples? Because if you mix things with DI pHs of, respectively, 2.23 and 2.74 you are going to get a pH between those values. They are only 0.5 pH apart. Thus if you simply randomly guess a number between 2.23 and 2.74 you can't be more than 0.05 pH off.

pH itself is a logarithmic scale. Why then is it wrong to apply logs (exponents) to the solution and instead go with what is essentially a linearized solution?

Because the log of the sum of a set of numbers is not equal to the sum of the logs of those numbers as you can easily verify. One can approximately estimate the pH of a mixture of weak acids (malts) from the following formula.

This formula can be tied to the chemistry and I've done that so many times here that I won't get into it again. It's in the Stickies. You MUST understand that chemistry to understand how to estimate mash pH. Note that the estimate is not simply the sum of the pH's weighted by the malt masses but by the product of the mass and buffering (a's) of each malt. You MUST understrand buffering in order to be able to estimate mash pH. Now if you assume that all the malts have equal buffering then the a's cancel out and you have the 3rd expression above. That is the simple average of the pH's weighted by the masses. Your suggested method is represented by the rightmost expression. For validity it would have to equal the 3rd expression and it doesn't because the log of a sum doesn't equal the sum of the logs.

Now note that the average weighted pH (3rd expression) is an approximation to the first expression and that in turn is an approximation because the estimate it represents is the first step in the solution of a non linear equation from an initial estimate of pH = 0. And even that first step is in error because we are ignoring the effects of water alkalinity and any thing we have added to it and are assuming that the malt buffering is linear (which it isn't though in many malts it is close to being linear). Thus your proposed method is invalid for many reasons the easiest of which to understand is that log(1 + 2 + 3 + 4 + 5) = 1.17609 ≠ 2.07918 = log(1) + log(2) + log(3) +log(4 )+ log(5)

 

[Silver_Is_Money]

Using the 'rejected' (even by me) simplistic logarithm scheme, If 1 lb. of DI_pH 4 malt (hypothetical, and admittedly likely to be the most acidic deep roasted malt ever encountered by man) is added to 10 lbs. of DI_pH 6 malt (wherein wheat malt would easily suffice here), the answer returned is pH 5 for the blended grist. If (for equivalent buffering) pH 4 is 100 times more acidic than pH 6 (such as it is) and pH 5 lies at a ten factor between them (such as it does), doesn't it seem as if the blended result (for the case of identical buffering) should indeed be right close to 5 pH?

This method (quasi-empirical as it is) does not result in predicted robust Stout or Porter mash acidities which are quite as radically low as does BW, but it seems to fall more toward the direction of pH's seen by several recent posting forum members who have measured and reported mash pH's of ~5 on the nose with respect to their robust stouts/porters. Plus I also recall @mabrungard claiming to have measured a stout that mashed at 4.9 pH, and ditto for member @dmtaylor. These are members who should be trusted to know their way around a pH meter.

 

[Silver_Is_Money]

I just applied the log method to Martin's "Reaper's Mild Stout" recipe which he measured at an honest mash pH of 4.9, and for the case of 102 ppm Ca++ in the mash water the logarithm method 'testing' spreadsheet kicked out a mash pH prediction of 5.00. Pretty close.

 

[ajdelange]

Using the 'rejected' (even by me) simplistic logarithm scheme, If 1 lb. of DI_pH 4 malt (hypothetical, and admittedly likely to be the most acidic deep roasted malt ever encountered by man) is added to 10 lbs. of DI_pH 6 malt (wherein wheat malt would easily suffice here), the answer returned is pH 5 for the blended grist.

(10^-4 * 1)/11 = 0.0000090909090...
(10^-6 * 10)/11 = 0.00000090909090...
sum = 0.00001
-log (0.00001) = 5.00 pH

Isn't that what would be expected?

No. In this simple case where the bufferings are linear and the same we can use the 3rd expression in the equation in No. 21 which tells us that:
pH = (1*4 + 10*6)/11 = 5.81818 ≠ 5 = -log((1*10^-4 + 10*10^-6)/11)

If (for equivalent buffering) pH 4 is 100 times more acidic than pH 6 (such as it is) and pH 5 lies at a ten factor between them (such as it does), doesn't it seem as if the blended result (for the case of identical buffering) should indeed be 5 pH?

When you put the pH 4 malt into water the H+ ion concentration is about 10^-4 and when you put the base malt into water the hydrogen ion concentration is 10^-6 which is 100 times more acidic with respect to pH 7. But as soon as you mix the two in water protons from the acid malt will immediately be absorbed by the base malt and this will continue until the base malt has absorbed 33.04 mEq of protons and the water 0.02 protons, all donated by the acidic malt (total 33.06 mEq). This happens when the pH is 5.8183 with respect to which pH we see that the two malts are just about equally acidic. This is how it clearly must be when there is nothing else to emit or absorb protons. The acidity of one with respect to mash pH must equal the basisicity of the other with respect to mash pH. I'll say it again (and again and again): you aren't going to understand this until you understand the basic chemistry of proton exchange in acid base reactions. You can try all kinds of things an never get the right answer unless you have an algorithm that sends protons to their correct destinations.

This method does not result in mash acidities which are quite as radically low as does BW, but it seems to fall more toward the direction of pH's seen by several recent posting forum members who have measured and reported mash pH's of ~5 on the nose with respect to their robust stouts/porters. Plus I also recall @mabrungard claiming to have measured a stout that mashed at just below 5 pH, and ditto for member @dmtaylor.

If I mix the two malts described here I am going to get a pH of 5.82. The chemistry dictates it. If mabrubgard and dmtaylor report pH of 5 they are not mixing these two malts or, if they are, they are bobbling their pH measurements. I will not, confronted with a couple of anecdotal readings, fudge the correct algorithm by a factor of 0.859402 to get an answer that agrees with theirs. In fact, of course, the first explanation is the most likely - they are mixing malts that are more acidic and/or less basic that these exemplars. At the same time, I would trust the pH readings of very few people who post here. The evidence that they don't know how to use pH meters is just too abundant.

 

[Silver_Is_Money]

If I mix the two malts described here I am going to get a pH of 5.82. The chemistry dictates it. If mabrubgard and dmtaylor report pH of 5 they are not mixing these two malts or, if they are, they are bobbling their pH measurements. I will not, confronted with a couple of anecdotal readings, fudge the correct algorithm by a factor of 0.859402 to get an answer that agrees with theirs. In fact, of course, the first explanation is the most likely - they are mixing malts that are more acidic and/or less basic that these exemplars. At the same time, I would trust the pH readings of very few people who post here. The evidence that they don't know how to use pH meters is just too abundant.

@mabrungard and @dmtaylor were referencing measured pH's for actual Stouts they mashed, and not my hypothetical test case. Martin specifically referenced 'Reaper's Mild Stout' in conjunction with an ~4.9 mash pH, and I found the recipe for this stout and whipped up the image seen above in an MME testing version which applies the simple log method. You are welcome to catch the recipe from the above image and run it through your Gen 2 spreadsheet to see what pH it gives you.

 

[ajdelange]

You are welcome to catch the recipe from the above image and run it through your Gen 2 spreadsheet to see what pH it gives you.

A Gen 2 spreadsheet using my measurements on Crisps Maris Otter and Kai's for the other two malts gives pH 5.28. As Martin is one of the few people here whose pH readings I would trust it is then clear that the numbers you gave do not represent the malts he used. What buffering value did you use? What Kolbach factor?

I just applied the log method to Martin's "Reaper's Mild Stout" recipe which he measured at an honest mash pH of 4.9, and for the case of 102 ppm Ca++ in the mash water the logarithm method 'testing' spreadsheet kicked out a mash pH prediction of 5.00. Pretty close.

If you are going to take what I give you and use it to learn something then perhaps I can help you. If you are going to brush it aside and proceed down a path which you have been shown leads in the wrong direction anyway then I can't help you.

My message then becomes directed to other the readers: Don't trust this man's spreadsheet.

 

[Silver_Is_Money]

My message then becomes directed to other the readers: Don't trust this man's spreadsheet.

Well, 5.00 is not more than a test bench toy at present, but I would entertain emailing a copy of 5.00 to those who are near the date of brewing a robust stout or porter so they can beta test it, but only if they intend to take a valid pH reading (measured at the 30 minute mark of the mash, and cooled to room temperature before taking the pH measurement, with a well calibrated meter ...). You are welcome to PM me. For that matter, if you are simply wanting to test it vs. the current MME or any other current spreadsheet for any recipe that you intend to brew soon and for which you will assuredly be taking a meter read (no pH paper allowed please) pH reading at room temp., send me a PM as well. I'll make it available for 3 days, through the upcoming Saturday.

 

[Silver_Is_Money]

The currently available for a free download on my website version 4.33 of 'Mash Made Easy' yields a 5.25 pH mash prediction for Reapers Mild Stout, as seen below. Pretty close to A.J.'s 5.28 mash pH projection.

 

[Silver_Is_Money]

Lastly, the OP's recipe and source water (including the 1.1 grams of baking soda which he added to the mash water, and thus the witnessed 50.7 ppm alkalinity in the mash water vs. 19.2 ppm alkalinity for his source water without the baking soda) as seen when passed through my log 10 based MME version 5.00 test edition. The 1.1 grams of baking soda he added to his 19.2 ppm alkalinity source water came very close to neutralizing all of the downward pH shift induced by his 2.75 gram each additions of calcium sulfate and calcium chloride. And thus the final predicted mash pH is 5.25 (pre the suggested addition of 3.43 grams of baking soda). This is still nowhere close to the 5.05 pH which the OP actually measured, but it's closer to it than what MME version 4.33 yields (which BTW is a mash pH prediction of 5.39 pH for the identical data input). I thus can't presently imagine any means of modeling an outcome projection of 5.05 pH for this recipe and source water combination which would match the meter verified observation of the OP.

 

[Rev2010]

Guys, I simply wanted to know which Calc was more accurate I am not looking for 100% accurate Calc, I just want one that is closest to the ballpark range. As this is only the first I've measured since my divorce/move/back into brewing ph reading I can only say that for this one reading Bru'n Water was closest in estimate. In the past in Jersey I used Brewers Friend and with a pH meter the results were so close to prediction. I only started looking at other calcs cause plugging in some recipe/water info gave me results that were noticeably different from that time over two years ago. Got to thinking the Calc was revisioned and made less accurate.

I measured a pH of 5.05 after a two step calibration after pulling the sample after 30 minutes than another 10 or so minutes cooling in the freezer. I've owned and used a pH meter before so I can't see how I'm so dense to have misused this tool.

I'm just going to continue using a few calcs and taking ph meter readings over the next few beers. The one that matches closest is the one I will use. I just don't want a calc that tells me to use a certain amount of lactic when another tells me opposite that I need to add alkalinity. For now I'll opt to risk the slightly higher end than the low end.


Rev.

 

[dmtaylor]

FWIW (nothing), the method I use (software + experience) would give an anticipated mash pH of 5.3 (yes, only 2 sig figs) for the OP's recipe. I too would doubt the 5.05...... however, I have also been surprised with some readings in the past and cannot say for sure which value is the correct one. Right answer might be in between, too. Like I say, 2 sig figs. I find my method has usually been good within 0.1, which is plenty good enough for me, especially seeing as how I don't think pH matters nearly as much as people like to freak out about it.

 

[ajdelange]

I've owned and used a pH meter before so I can't see how I'm so dense to have misused this tool.

Usually the problem (if, in fact, there is one) arises when people fail to check the stability of their electrodes from time to time. They assume that their readings are accurate because they have calibrated their meters. Another common cause of inaccurate readings is allowing the meter to make the decision as to when to accept the calibration reading. Always do that manually and only when you (not some algorithm in the meter) are convinced that the reading is stable.

No one is saying that your measurement of 5.05 isn't valid. It may be valid. It just isn't very likely that it is given the data available to us. When something doesn't look right often it isn't right and it is well worth checking into. Years of experience have taught me that the first thing to suspect is the pH meter. Time and time again that has proven to be cause of the discrepancy. Your practices in pH measurement may be spot on but I have no way of knowing that. I see lots of responses here like "Yes, I calibrated the meter. It was the first thing I did when I got it last year." (well maybe not lots but I have seen that). If you are following the protocol set out in the Sticky on pH meter calibration then you can trust your pH measurements. If you are cutting corners - well then you can't be so sure.

There is no such thing as a 100% accurate calculator. There are calculators that are very accurate if given accurate malt data and I used one but I don't have accurate malt data to put into it - only, in this case, what I measured for a bag of the same malt from the same maltster but not the same bag you used. Data for the other malts I took from Kai's somewhat primitive and, at this point, old measurements.

 

[Silver_Is_Money]

I see lots of responses here like "Yes, I calibrated the meter. It was the first thing I did when I got it last year."

I always get a good chuckle out of that one!!!

 

[balrog]

I sit on the outside, watching all these discussions, wondering about getting a pH meter - and I keep coming to the conclusion that if I don't do some sort of titration method I can never really know the pH.

 

[Rev2010]

No one is saying that your measurement of 5.05 isn't valid. It may be valid. It just isn't very likely that it is given the data available to us. When something doesn't look right often it isn't right and it is well worth checking into.

Agreed, and the thought that possibly the reading was off only makes me feel better cause I didn't intend for the pH to be that low. I usually shoot for 5.4. But, I also tend to agree that I think people over panic too about pH. I'm not bothered by the reading I got, just glad it didn't show below 5 - though you say it's virtually impossible with immense acid additions to go below 5 with just the grain and water correct?


Rev.

 

[ajdelange]

I sit on the outside, watching all these discussions, wondering about getting a pH meter - and I keep coming to the conclusion that if I don't do some sort of titration method I can never really know the pH.

You will need to do titration if you want to use software to predict pH and get the best results. You do not need to do any titration just to determine mash pH or to get an idea what it will be. Simply take a portion of the planned grist and mix it with strike temperature water. Wait a few minutes, withdraw a sample and cool. Check the pH. If it is too high, add some acid or acid malt. If it is too low try again with less acid or add some base. OK, technically you are titrating when you do this but it's not the detailed lab procedure required to characterize the malt.

 

[ajdelange]

I'm not bothered by the reading I got, just glad it didn't show below 5 - though you say it's virtually impossible with immense acid additions to go below 5 with just the grain and water correct?

Not quite. I'm saying that it is unlikely (I won't go as far as "virtually impossible") that you will see a mash with these grains below or even close to 5.0 without added acid.

 

[Rev2010]

Not quite. I'm saying that it is unlikely (I won't go as far as "virtually impossible") that you will see a mash with these grains below or even close to 5.0 without added acid.

Sorry, that was a typo. Was indeed supposed to say "without immense acid additions". Thanks!


Rev.

 

[ScrewyBrewer]

If this helps somewhat: Per Briess data, the DI pH of their 2-Row Brewers malt is about 5.57, the DI pH of their 10L Bonlander is about 5.50, and the DI pH of their 10L crystal is about 5.12. The 60L Caramel is about 4.75 DI_pH. The 350L Chocolate is about 4.7 DI_pH. I don't know what the typical DI_pH for debittered black 550L is, but I would guess perhaps 4.5 to 4.6 pH.

An interesting observation when using Riffe's formula Briess 2-Row calculates to 5.723 pH and Briess Crystal 60L to 5.678 pH.

 

[ScrewyBrewer]

Simply take a portion of the planned grist and mix it with strike temperature water. Wait a few minutes, withdraw a sample and cool. Check the pH. If it is too high, add some acid or acid malt. If it is too low try again with less acid or add some base. OK, technically you are titrating when you do this but it's not the detailed lab procedure required to characterize the malt.

I think you've just touched on a 'congress' mash using a percentage of grains used in an actual recipe. While this approach doesn't provide granular values for each individual grain pH it will provide insight into a recipe's mash pH.