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Home Brew Forums > Home Brewing Beer > Brew Science > Bru'n Water predicted 5.41, I ended up at 5.13. What did I do???
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Old 08-24-2014, 04:02 PM   #1
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Default Bru'n Water predicted 5.41, I ended up at 5.13. What did I do???

I brewed a mild ale yesterday and had a totally unexpected result on my pH. The grain bill was:

8 lb 9 oz Maris Otter
2 lb 10.3 oz Crystal 60
10.6 oz Chocolate malt

10 gallon batch size with expected OG of 1.037. Mashed at 1.4 qts. per lb.

In DI water, Bru'n water predicted a pH of 5.1 with no additions. I did a 1 lb. test mash in 1.4 quarts of DI water and came up with 5.09 pH. I was pretty confident at this point.

So I built up water using the mild ale profile in Bru'n Water and used this:

Reaper's Dark Mild

Starting Profile ppm
Ca 0
Mg 0
Na 0
SO4 0
Cl 0
HCO3 1

Finished Profile ppm
Ca 87
Mg 3
Na 21
SO4 40
Cl 58
HCO3 183

Hardness 227 (ppm as CaCO3)
Alkalinity 151 (ppm as CaCO3)
RA 88
SO4/Cl 0.69

Batch Volume 10.00 Gallons
Total Mash 4.21 Gallons
Mash Dilution 4.21 Gallons
Total Sparge 10.13 Gallons
Sparge Dilution 10.13 Gallons

Mineral Additions Mash (g) Sparge (g)
Gypsum . 0.8 2.0
Epsom Salt 0.4 1.0
Canning Salt 0.8 2.0
Baking Soda 0.0
Calcium Chloride 0.8 2.0
Chalk . 0.0
Pickling Lime 1.8
Mag Chloride 0.0 0.0

Bru'n Water predicted 5.41 pH using these additions. I checked the pH at 5 minutes into my mash and got a reading of 5.09. Because of the wild difference, I didn't panic and figured I had something wrong with my measurement. I recalibrated the meter and checked the mash again at 15 minutes. It was 5.11. I checked the meter against the 4.01 solution and it read 4.02. I'm new to this, but I'm fairly confident in my testing procedure, so I don't think it was a meter problem. At 60 minutes, the mash measured 5.13.

So I figure something must have been wrong with my additions. What could I have done to have an actual reading this far off from what I was hoping for? Did I mis-measure one of my brewing salts?

Probably not coincidentally, I undershot my expected gravity by 4 points (1.033 instead of 1.037), which wouldn't be a big deal if my beer were a high gravity beer, but with this style, 4 points is a lot. I always either overshoot or hit my numbers dead on. I'm guessing that the low pH affected my efficiency.

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Old 08-24-2014, 05:15 PM   #2
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Why did you do the test mash with DI water rather than your "adjusted" water? Admirably you did a test mash but if you had used your "adjusted" water in the test mash, the low pH situation in the actual mash could have been discovered.

Edit: The reason I ask is if you measured out your additions accurately it may be that the predicted pH just didn't line up with your actual mash pH and there was nothing you did to cause that.

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Old 08-24-2014, 05:17 PM   #3
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Default Bru'n Water predicted 5.41, I ended up at 5.13. What did I do???

There is probably a standard purity assay for lime. In the meantime, add a few drops of acid to your pickling lime. Does it fizz? Where did you get it? Grocery store pickling brand?

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Old 08-24-2014, 05:56 PM   #4
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Originally Posted by IKR View Post
Why did you do the test mash with DI water rather than your "adjusted" water? Admirably you did a test mash but if you had used your "adjusted" water in the test mash, the low pH situation in the actual mash could have been discovered.

Edit: The reason I ask is if you measured out your additions accurately it may be that the predicted pH just didn't line up with your actual mash pH and there was nothing you did to cause that.
Now that you ask this, I remember something. I did the test mash without any pickling lime, but I had measured out the pickling lime to add after I mashed in so I could test the pH before and after. I added the pickling lime after 5 minutes, but there was no change to the pH. At the time, I figured that the problem was that my scale reads to .1 gram, but that it was difficult to get a reading on the scale for just .1 gram, which is what the 1 pound test mash called for to get the pH up to 5.4. Now that you ask, it could be that I measured correctly for the test mash but that the lime wasn't effective.

My pickling lime is a grocery store brand. Does it go bad? How would I test it?
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Old 08-24-2014, 06:31 PM   #5
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Hmm? That Reaper's Mild recipe is one that I've brewed before and it is one of the most acidic grists I've experienced. It is one of the data points that ultimately helped calibrate the pH prediction model in Bru'n Water.

It is very odd that the measured pH was substantially lower than the prediction. As others on this list have reported, there is no way that the pH should end up this low. However as the OP and I have found, they are wrong. Everyone says that Bru'n Water predicts an overly low pH, so there must be something wrong with the lime used. As Pushrods suggests, I suspect that the lime may be off. A test of the lime can be performed by putting drops of acid on a small amount of the lime. If the mixture fizzes, the lime is bad...some of the lime has converted to chalk. As some folks have heard me say, chalk is a poor alkalinity producer since it doesn't properly dissolve in the timeframe we brewers need it to work in.

I look forward to hearing the OP's findings.

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Old 08-24-2014, 09:44 PM   #6
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Quote:
Originally Posted by CadiBrewer View Post
I brewed a mild ale yesterday and had a totally unexpected result on my pH. The grain bill was:

8 lb 9 oz Maris Otter
2 lb 10.3 oz Crystal 60
10.6 oz Chocolate malt

10 gallon batch size with expected OG of 1.037. Mashed at 1.4 qts. per lb.

In DI water, Bru'n water predicted a pH of 5.1 with no additions. I did a 1 lb. test mash in 1.4 quarts of DI water and came up with 5.09 pH. I was pretty confident at this point.
Confronted with a situation like this the first question one asks is "Are those numbers reasonable?" I realize that as a relative newcomer to all this that isn't an easy question to answer. But that's what those of us with more experience are here for.

Maris Otter is a fairly dark "pale" malt with a DI mash pH of about 5.6. I don't know what its effective buffering capacity is but something like -40 mEq/kg-pH wouldn't be attypical. Based on this it is going to take a fair amount of acid, something like 104 mEq to move 8-1/2 lbs of it to pH 5.1 - the prediction we are checking. That's a lot to ask of the quantities of chocolate and caramel you have specified which, together, to 5.1, might be expected to supply a bit less than half the required amounts. So unless you have super caramel and super chocolate malts that are twice as acidic as typical examples of those malts or a base malt with half the buffering capacity of a typical base malt 5.1 does not seem like a reasonable mash pH. A more reasonable number would be near 5.3

We have to put against this, of course, the fact that you got a confirmatory test mash pH. So we are suspicious of the prediction and the measurement at this point though we recognize that it is possible to have a pH this low for a mash of this composition with DI water. That's what experience would tell you at this point - that you should be suspicious. The response to this suspicion would involve recalibration of the pH meter, calibration checks and repeated measurements on the test mash, individual measurement of the the three malts to see if their DI pH's fit expectations....

Quote:
Originally Posted by CadiBrewer View Post
So I built up water using the mild ale profile in Bru'n Water and used this:

Reaper's Dark Mild

Starting Profile ppm
Ca 0
Mg 0
Na 0
SO4 0
Cl 0
HCO3 1

Finished Profile ppm
Ca 87
Mg 3
Na 21
SO4 40
Cl 58
HCO3 183
Your water after the addition of the salts you used contains NO bicarbonate. Bru'n water insists on using bicarbonate as a proxy for alkalinity. As we see here it isn't and the program should be fixed. This has been discussed at length before.

Quote:
Originally Posted by CadiBrewer View Post
Hardness 227 (ppm as CaCO3)
Alkalinity 151 (ppm as CaCO3)


Mineral Additions Mash (g) Sparge (g)
Gypsum . 0.8 2.0
Epsom Salt 0.4 1.0
Canning Salt 0.8 2.0
Baking Soda 0.0
Calcium Chloride 0.8 2.0
Chalk . 0.0
Pickling Lime 1.8
Mag Chloride 0.0 0.0

Bru'n Water predicted 5.41 pH using these additions.
Now that is a reasonable mash pH prediction with the salt additions you have made. The DI mash calculated 5.29 and adding the salts and lime you used gives 5.43. So now suspicion reigns again. You got a prediction that seems reasonable when the salts are included and one that doesn't for a DI mash. Even though the with salts prediction is reasonable...

Quote:
Originally Posted by CadiBrewer View Post
I checked the pH at 5 minutes into my mash and got a reading of 5.09. Because of the wild difference, I didn't panic and figured I had something wrong with my measurement. I recalibrated the meter and checked the mash again at 15 minutes. It was 5.11. I checked the meter against the 4.01 solution and it read 4.02. I'm new to this, but I'm fairly confident in my testing procedure, so I don't think it was a meter problem. At 60 minutes, the mash measured 5.13.
...you get a pH meter reading which conflicts with that reasonable prediction. You did the right thing in recalibrating and checking the 4 buffer after the recal so at this point we are pretty mystified. The buffer? Was it fresh? Not past its expiry date? Never been used before?

Quote:
Originally Posted by CadiBrewer View Post
So I figure something must have been wrong with my additions. What could I have done to have an actual reading this far off from what I was hoping for? Did I mis-measure one of my brewing salts?
As it would be unusual to obtain a reading this low with no lime let alone with lime the only salt measurement error we can conceive is if you added 5 times as much calcium as you intended to.

I'll just point out that when people start making a new measurement (pH in this case) mysterious things happen that just stop happening as experience is gained with the new technique/equipment etc. So hang in there.
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Old 08-25-2014, 06:30 AM   #7
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No one has asked a major question......

At what temperature are you testing Ph? Room temp sample or 120f+ &/ or mash temp?

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Old 08-25-2014, 03:58 PM   #8
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A Gold Star for ITsPossible!

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Old 08-25-2014, 07:44 PM   #9
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No one has asked a major question......

At what temperature are you testing Ph? Room temp sample or 120f+ &/ or mash temp?
Thanks for the input. The tests have all been at room temperature.
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Old 08-25-2014, 09:23 PM   #10
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Confronted with a situation like this the first question one asks is "Are those numbers reasonable?" I realize that as a relative newcomer to all this that isn't an easy question to answer. But that's what those of us with more experience are here for.
...I'll just point out that when people start making a new measurement (pH in this case) mysterious things happen that just stop happening as experience is gained with the new technique/equipment etc. So hang in there.
I checked my lime last night and with a few drops of 10% Phosphoric acid, and the lime fizzed. I suspect that is the problem with the pH readings being the same both before and after the salt additions. I have a clean, unopened bag of lime that I'll use again on a test mash and see what happens.

As for the low pH readings on the DI test mash and on the real thing, my calibration solutions were both new and opened freshly for the test mash. They are a brand that I'm not used to, called General Hydroponics. They are not past their expiration date, so I don't think that's the problem. I do store them in a hot, Southern California garage which can't be optimal, so I'll start with fresh solutions and begin storing that kind of thing in the house from here on out.

I'm interested in learning more about this conundrum, so I intend to not only run a test mash with my grain bill in DI water, but I intend to add the lime and other salts to see what my end result is. I also intend to mash a small amount of each of the three grains separately in DI water so I can find the DI pH of each. I hope that this will lead to learning, as well as practice with all of my techniques.

Question for AJ - is there a standard for the amount of grain and water to use for the three separate grains when I do test mashes on each? For my test mashes, I use my normal rate of about 1.3 quarts per pound, but for discerning the DI pH of various grains in the Water book, what was the "standard"? Secondly, is there a way to estimate the buffering capacity of the Maris Otter without having access to lab grade equipment?

I appreciate all of the help given here.
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