Alkalinity, Ward Report and Bru'N Water Issue

[nhraj700]

For years, I have always struggled with achieving a desirable mash ph with my lighter beers. After lurking in this forum for some time and reading the Water book, I knew what I needed to do, get a water report and look into water adjustment. A quick look at the free version of Bru’ N Water and subsequent donation to obtain the enhanced version was definitely a step in the right direction too. But here is my dilemma...

I received my Ward Water report and applied what I generated in Bru’ N Water to my first brew using some lactic acid and brewing minerals. Water modification definitely helped, but I still missed my ph target(s). I tried it again with another brew and same result. So on the third brew session, I really spent some time slowly adding acid for the sparge water and precisely measuring each addition to get to 5.6 PH. I am noticing in my situation, Bru’ N Water is undershooting the necessary acid by about 15%. Using a 15% acid boost to my mash water, for the first time I got my mash to 5.3 ph. Woohoo.
So here is the kicker. If I use the Bicarbonate value supplied by Ward, 91 ppm, I undershoot the acid addition. If I use Bru’ N Water’s estimated figure of Bicarbonate (102.5 ppm) in Row 14 using the 8.1 PH and Total Alkalinity of 85 ppm reported by Ward, my acid addition matches almost perfectly with the acid I need to get my mash and sparge ph down. So here is my water report from Ward.

Total Dissolved Solids (TDS) Est, ppm 137
Electrical Conductivity, mmho/cm 0.23
Cations / Anions, me/L 2.4 / 2.3 ppm
Sodium, Na 13
Potassium, K 2
Calcium, Ca 26
Magnesium, Mg 6
Total Hardness, CaCO3 90
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S 6
Chloride, Cl 5
Carbonate, CO3 6
Bicarbonate, HCO3 91
Total Alkalinity, CaCO3 85
Total Phosphorus, P 0.13
Total Iron, Fe < 0.01 "<" - Not Detected / Below Detection Limit

I have two questions regarding Bru’ N Water and one general question.

1. This question isn’t directly related to my issue, but I noticed when using the enhanced version of Bru’ N Water and in the Water Report Info worksheet, I noticed that inputting an entry into A14 (Reported Total Alkalinity) of 85 and an entry into B14 (Reported PH) of 8.1 results in a calculated formula in D14 of 0.6 PPM estimated Carbonate value. Shouldn’t it be 6 ppm that perfectly matches my water report or is this even the same? Seems like it is off 10 fold
2. Is it acceptable to use Bru’ N Water’s estimated 102.5 ppm of Bicarbonate in lieu of Ward’s 91 ppm figure? Two benefits occur when not using Ward’s Bicarbonate value, the cation/anion difference balances to zero and I seem to hit my ph targets because the acid is boosted.
3. Regarding my Ward report, general thoughts on the water and the report itself? Because of this issue, I wonder if the report is somehow flawed. Seems like my water isn’t too bad. I’ve seen worse water reported by some of the folks on here.

 

[ajdelange]

Ward Labs does not calculate bicarbonate and carbonate correctly from the things they measure which are alkalinity and pH. For a reported alkalinity of 85 and a pH of 8.1 assuming 20°C and an alkalinity titration end point of 4.4 (which is, I believe, what Ward Labs uses) the bicarbonate is 100.97 and the carbonate 0.64 mg/L. Without going into all the nuances of how these are calculated we can look the the second step which is to calculate the ratio of carbonate to carbonic. This is simply 10^(pH - 10.38) = 0.0053. Calculating 91*0.0053 = 0.48 it's plain that that is pretty far from 6. How they get 6 is beyond me. There are some old formulas that apply whatever the composition of the water but the precise calculations I have given depend on the sole source of alkalinity being carbonate, bicarbonate and hydroxide ions. I suspect they are using the rules of thumb as they are really in the agriculture business where there is probably lots of phosphate around of which you have a smidgeon too so your bicarbonate and carbonate content numbers would, in order to justify the two decimal places I have shown, really need to be adjusted. But the ratio would still be the same (it is really 0.0064 because of the other ions in the water).

Yes, the report is flawed as discussed. Bobbling the carbonate content also screws up the ion balance calculation when pH is high enough, as it is in your case. This is, in part, why I try to get people to think in terms of alkalinity rather than bicarbonate and carbonate. Most spreadsheets seem to want people to enter bicarbonate and use alkalinity if they don't have bicarbonate. It should be the other way around as bicarbonate is calculated from alkalinity and sometimes, as in Ward Labs reports, not calculated correctly. Fortunately, for more nominal pH than yours, the errors are small.

 

[mabrungard]

If you just convert that alkalinity value into an equivalent bicarbonate concentration, I come up with almost 104 ppm.

I'm assuming that you may not have input that 6 ppm carbonate value in the water report input. With both of the bicarb and carb input, the alkalinity value does agree with the Ward report. In addition, the bicarbonate value shown on the Water Adjustment sheet for the Existing Water Profile is 103 ppm.

By the way, that is a pretty nice brewing water. Just attend to neutralizing the alkalinity as needed and you will do fine.

 

[ajdelange]

If you just convert that alkalinity value into an equivalent bicarbonate concentration, I come up with almost 104 ppm.

Which is close to the actual 101 and a pretty good estimate (< 3% error). pH 8.1 is just getting into the area where the simple conversion is beginning to fall short. This (estimate the bicarbonate as equal to the total alkalinity as CaCO3 which is, as the ion, 61*T/50) is what Standard Methods says you should do if P = 0 (which it will be for any pH < 8.3) with the caveat that "...ion concentrations in the strictest sense are not represented in the results,..."

With both of the bicarb and carb input, the alkalinity value does agree with the Ward report.

I think Martin may have cracked the code, or at least part of it here. Apparently they come up with their bicarb number, which isn't enough to explain the all the alkalinity, T, and then assign the unexplained part to carbonate. The real question then is how they come up with a bicarbonate number that is, in this case, about 10% low. They must know they are violating Henderson-Hasselbalch (the ratio thing) wrt carbonate/bicarbonate. If they did what Standard Methods suggests they would call bicarbonate 104 and carbonate 0.0053*104 = 0.55 (not considering ionic strength) and be pretty accurate. And they should be following Standard Methods. Well, that would be true if they were in the potable/waste water industry but they are in the irrigation water industry and I think that's where the difference may lie. Confusing to us brewers though.

 

[ajdelange]

They calculate carbonate and bicarbonate using the method in USDA Handbook No. 60 (they are soil chemists) which is identical to the method proposed by AWWA in Standard Methods. Thus the "...ion concentrations in the strictest sense are not represented in the results,..." caveat still applies. The discrepancy in this case is that they do P alkalinity titration to pH 8. P alkalinity is defined at pH 8.3 (the USDA manual says to add acid until the phenolpthalein color is gone - that should happen at pH 8.2). In going beyond pH 8.3 (8.38, actually) they are using acid to convert some bicarbonate to carbonic but this gets counted as converting carbonate to bicarbonate. Thus carbonate is calculate too high and bicarbonate too low. I've made them aware of the problem and they are looking into fixing it. This would not be a problem for any sample with pH < 8 as they would get P=0 for any such sample. The problem comes with samples 8 < pH < 8.38 all of which should give P=0 but which read P > 0 for titration to pH 8.

 

[nhraj700]

AJ and Martin,

Thank you so much for getting to the bottom of why I was pulling my hair out. It sounds like Ward Labs really threw me an unexpected curve ball with my water report.

Ward Labs does not calculate bicarbonate and carbonate correctly from the things they measure which are alkalinity and pH. For a reported alkalinity of 85 and a pH of 8.1 assuming 20°C and an alkalinity titration end point of 4.4, the bicarbonate is 100.97 and the carbonate 0.64 mg/L. But the ratio would still be the same (it is really 0.0064 because of the other ions in the water).

If you just convert that alkalinity value into an equivalent bicarbonate concentration, I come up with almost 104 ppm.

So based on both of your comments, what should I adjust the Bicarbonate and Carbonate values to in the spreadsheet so it will hopefully put this issue to rest in my situation? In my 8 gallons of sparge water, the recommended addition originally called for 3.8 ml of lactic to get to 5.6 ph, but my tests put it closer to 4.4 ml of lactic acid. When I changed the Bicarbonate value from 91 ppm to 103 ppm in the spreadsheet based on the estimated value below the ion table, it reflected the right lactic acid addition, but I didn't adjust the Carbonate value as I didn't know that was messed up too or realize the ratio needed to be accounted for.

Yes, the report is flawed as discussed. Bobbling the carbonate content also screws up the ion balance calculation when pH is high enough, as it is in your case.

Based on your confirmation of the flaw, should I be concerned about anything else in the report? Does this flaw affect anything else they are reporting on?

I'm assuming that you may not have input that 6 ppm carbonate value in the water report input. With both of the bicarb and carb input, the alkalinity value does agree with the Ward report. In addition, the bicarbonate value shown on the Water Adjustment sheet for the Existing Water Profile is 103 ppm.

I did enter the carbonate value as 6. Attached is a screen shot of how I initially set it up before the discovery that it seemed the acid addition wasn't enough.

By the way, that is a pretty nice brewing water. Just attend to neutralizing the alkalinity as needed and you will do fine.

That is good to know. Historically my beer has been pretty good. But based on the whole mash PH not being down where I wanted it, there was room for improvement. I want to get this alkalinity figured out so I can tackle a maibock.

I've made them aware of the problem and they are looking into fixing it.

That is awesome. Thanks for doing that. It's a win/win for Ward and the brewing community.

 

[ajdelange]

Thank you so much for getting to the bottom of why I was pulling my hair out. It sounds like Ward Labs really threw me an unexpected curve ball with my water report.

Not really. As explained below you don't really need to know either bicarbonate or carbonate. What is important are alkalinity and pH and your report gives you accurate versions of those.

So based on both of your comments, what should I adjust the Bicarbonate and Carbonate values to in the spreadsheet so it will hopefully put this issue to rest in my situation?

The 'correct' answer for bicarbonate is 101 mg/L. The Standard Methods approximation is 104 mg/L. The 'correct' answer for carbonate is 0.68 mg/L. The Standard Methods approximation is 0. It won't much matter which you use. There is sort of a circular argument at play here. You don't really need to know either bicarbonate or carbonate. The only reason for calculating them is for a QC check on the analysis based on the anion/cation balance. Unfortunately many calculator and spreadsheet authors seem to think of bicarbonate as the fundamental quantity and appear to effectively wind up calculating alkalinity from it. This is adequate in most cases. You, with your pH on the edge, are exceptional though the errors are still modest (around 3%).

In my 8 gallons of sparge water, the recommended addition originally called for 3.8 ml of lactic to get to 5.6 ph, but my tests put it closer to 4.4 ml of lactic acid. When I changed the Bicarbonate value from 91 ppm to 103 ppm in the spreadsheet based on the estimated value below the ion table, it reflected the right lactic acid addition, but I didn't adjust the Carbonate value as I didn't know that was messed up too or realize the ratio needed to be accounted for.

Again, you don't need to know the bicarbonate or carbonate - only pH and alkalinity so in a robust calculation you would not have had a problem. Since you are using a spreadsheet based on bicarbonate you should use an accurate bicarbonate number: 101 or 103.

Based on your confirmation of the flaw, should I be concerned about anything else in the report? Does this flaw affect anything else they are reporting on?

I don't think so. Bicarbonate and carbonate are calculated from measurements and have been slightly miscalculated up to now. They understand what the problem is and are taking steps to resolve it so in the near future the discrepancy should be gone. I suppose that we could conclude that if they misinterpreted the meaning of P alkalinity they could misinterpret the meaning of M alkalinity too but that would make very little difference as the charge on the carbo system is nearly 0 at any pH near 4.4.

That is awesome. Thanks for doing that. It's a win/win for Ward and the brewing community.

And me too. Now I can explain this and it's been bugging me for years. Wish I'd done it sooner!

 

[ajdelange]

Motivated by this thread I put the method for calculating carbonate and bicarbonate from alkalinity and pH in a Sticky.

 

[HungusBrews]

I know its not Ward Labs, but came across this and thought it may be a good thread to add this information to. Is the Lamotte Brew Lab bicarbonate calculation also incorrect? In their directions they say to multiple total alkalinity by 0.61 to convert to bicarbonate. Shouldn't this conversion factor be 1.22? Here is a link to the directions with the reference on page 8.

https://www.lamotte.com/images/pdf/instructions/7189-01.pdf

 

[ajdelange]

That's a good question. There is an inconsistency with the 0.61 factor. It should indeed be 1.22. There are two possibilities here. One is that they calculate alkalinity correctly and use the wrong conversion factor. The other is that they think ppm as CaCO3 is 100*mEq/L. I have seen other kit manufacturers make that error.

On their web page they have an "Ask a Question About this Product" window. I asked a question about this but never got a reply. In another thread I mention that someone with one of these kits needs to do a check to see which of the two possibilities pertains. 84 mg of NaHCO3 in a liter of water should read 50 ppm as CaCO3.

 

[ajdelange]

Interestingly enough I just got an e-mail from them saying that they are going to change the conversion factor in their instructions and they have, in fact, done so. This implies that the measurement calculation (drops to ppm as CaCO3) is correct.

 

[HungusBrews]

Excellent! Hopefully they send out some kind of email or facebook post to let current users know. I emailed them about it a few days ago and got no response. I guess yours looked more official.


Sent from my iPhone using Home Brew

 

[ajdelange]

Judging from the timing it is the power of HBT!

 

[HungusBrews]

Ran into the LaMotte guys at NHC. This has been corrected and revised on their instruction sheet. https://www.lamotte.com/images/pdf/instructions/7188-01.pdf

 

[ajdelange]

LaMotte made the correction back on 5/20. I am still waiting to see confirmation that Ward has made the fix but no one has posted a report with pH>8 recently.


Sent from my iPhone using Home Brew

 

[mabrungard]

Through the nudging of AJ, the Lamotte rep did have Palmer review the alkalinity calc. John also helped Lamotte alter the testing kit contents to better fit what we brewers want to know. That kit originally included a chlorine test kit. John got them to change that to a chloride test kit. In addition, the test kit includes tests for all major brewing ions excepting sodium. To arrive at an estimate of sodium content, they assume that the difference between the cation and anion totals is equal to the sodium content. While that is not always true, it should be close enough in most cases. In the UK, Murphy's provides water testing and they also omit the sodium result. I've long counseled UK brewers to perform a similar calculation to estimate their sodium content.

At a $130 for the Lamotte brewers test kit, its a little pricey. However if your water quality varies, this kit may be worth every penny.