pH Meter vs 5.2 pH Stabilizer

Hiya folks,

A question:

pH meter = $50 (approx.)
1lb of 5 star 5.2 pH stabilizer = $10

Is there any advantage to manually testing and adjusting one's mash pH versus just using the stabilizer?

I don't mind the work and price of manual adjustment if there's a good reason.

Thanks in advance for your bounty of knowledge, HBT.

Rob

pH meter = only measures your pH

5.2 = purports to keep your mash in that range....

Tough call, as the meter doesn't "change" anything and the 5.2 may or may not do anything......depending on your water....

https://www.homebrewtalk.com/f128/5-2-ph-stabilizer-post-your-results-169092/

You can't have both because the pH meter will stop the 5.2 from working properly. This is said with tongue firmly in cheek based on dozens of reports that 5.2 is the greatest thing since sliced bread from people who don't measure pH at all or use strips whereas those who use pH meters find that this product does not bring mash pH to 5.2. It really couldn't be expected to unless inordinate amounts of it are used as it has little buffering capacity. A buffer should never be designed for a pH more than 1 unit removed from the closest pK of the acid involved (phosphoric here - nearest pK 7.2 i.e. 2 pH units away). Beyond this it seems to buffer at 5.99 (in distilled water) i.e. the powder is a buffer designed for that pH rather than 5.2. Analysis of the sodium concentration confirms this. This has lead me to wonder whether they are relying on the malt to provide extra monobasic phosphate thus establishing a buffer closer to 5.2 but this is really a desperate attempt on my part to give them some credit for knowing what they are doing (in the chemistry sense - the stuff is sold in every LHBS and mail order catalogue so they do seem to know what they are doing in the marketing sense).

So the serious answer to your question is that 5.2 cannot be relied on to establish proper mash pH. A pH meter will show you that. Or you can take our word for it and save the money on the 5.2. The pH meter is one of the best investments you can make in brewing. Learn how to use it and it will help you to establish proper mash, kettle, and fermenter pH.

2oz of gypsum - $0.99
Package of baking soda - $2
Actually being able to adjust your pH once you take a reading - priceless

Seriously though, it's not really fair to compare price on a pH buffer and pH meter. If you're looking at measuring pH it's more fair to compare the pH strips to the meter. A vial of 100 beer range pH strips is around $5. I use the strips personally simply because I've just started all grain in the last few months and haven't dropped the money on a meter yet, so I can't comment on how accurate they are in relation to the meter. They do seem to work to me though. I like using baking soda and gypsum to adjust my pH since they're pretty easy to get and cheap, and I can adjust up or down as I wish and test again to see if it had the effect I wanted. I'm probably going to get a meter eventually, for now this works ok and still costs less than $10 to actually have a decent idea of what's going on with your water.

ajdelange said:

So the serious answer to your question is that 5.2 cannot be relied on to establish proper mash pH. A pH meter will show you that. Or you can take our word for it and save the money on the 5.2. The pH meter is one of the best investments you can make in brewing. Learn how to use it and it will help you to establish proper mash, kettle, and fermenter pH.

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Thanks, ajdelange. Your opinion seems very well informed. Your answer is what I expected, but I figured it couldn't hurt to ask before dropping the cash on the pH meter.

It's not just the meter either, you really need the storage solution and the two calibration solutions. Still, in the grand scheme it's not that expensive. I still need to pull the trigger myself.

ajdelange said:

You can't have both because the pH meter will stop the 5.2 from working properly.

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Has brewing finally entered the realm of quantum mechanics? AWESOME! :rockin:

pH meter = $50 (approx.)
1lb of 5 star 5.2 pH stabilizer = $10

Is there any advantage to manually testing and adjusting one's mash pH versus just using the stabilizer?

Click to expand...

pH meter is also very handy if you want to make wine (especially red wine).

I have to agree with the above, the premise of the question is only valid if the 5.2 tabs always work. But, from what I've learned, they don't always work.

I've been shown that the pH buffer was not keeping my mash in the proper range, likely the cause of my piss-poor efficiency. I'd like to invest in a meter at some point, right now I'm still kind of winging it. The strips, even the "good" Colorphast strips, aren't perfect, either; they tend to read off by upwards of 0.3.

I am also in the market for a pH meter as ajdelange has steered me from the 5.2 Stabilizer as well. Does anyone have a recommendation for a reliable pH meter? I'm looking to spend somewhere between $50-80, although I would not hesitate to buy a cheaper one if it is accurate and well made. Right now I've narrowed my choices down to the Hanna Phep-5 or Milwaukee Tester SM101 as recommended by Kaiser. Thanks as always.

philbert119 said:

I am also in the market for a pH meter as ajdelange has steered me from the 5.2 Stabilizer as well. Does anyone have a recommendation for a reliable pH meter? I'm looking to spend somewhere between $50-80, although I would not hesitate to buy a cheaper one if it is accurate and well made. Right now I've narrowed my choices down to the Hanna Phep-5 or Milwaukee Tester SM101 as recommended by Kaiser. Thanks as always.

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Those are probably the best two choices in your price range.

The tradeoff is a standard probe connection vs ATC.

remilard said:

Those are probably the best two choices in your price range.

The tradeoff is a standard probe connection vs ATC.

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So the standard probe connection allows you to change out your probe when they wear out?

Isn't it better/necessary to cool your wort to avoid stressing the meter probe? So it seems like ATC wouldn't really accomplish all that much...

bopgun23 said:

Is there any advantage to manually testing and adjusting one's mash pH versus just using the stabilizer?

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Yes. It's not just about pH. Brewing ions like Ca+, SO4-, Mg+, etc are very important to the process and relying solely on the pH stabilizer product does nothing towards having them in proper amounts in the mash and brew. On the other hand if your brewing ions are adjusted properly for the beer not only will your mash pH be in the correct area your beer will have the right minerals and micro-nutrients to provide for good enzyme action, better mash runoff, yeast health and all sorts of good things.

bopgun23 said:

So the standard probe connection allows you to change out your probe when they wear out?

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No, you can replace the non-standard probe on the Hanna with the same non-standard probe. But you have no choice and you can't upgrade (the probe is the important part).

Isn't it better/necessary to cool your wort to avoid stressing the meter probe? So it seems like ATC wouldn't really accomplish all that much...

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That depends. How much effort do you want to put into bringing every sample to exactly the same temperature before measuring? You can do the TC yourself, but ATC is a nice to have. To be clear the meter will only give a correct pH at the reference temperature (without correcting), this is a function of how the meter works. This is a completely separate issue from the pH truly being lower at higher temperatures, which ATC doesn't correct for anyway.

remilard said:

To be clear the meter will only give a correct pH at the reference temperature (without correcting), this is a function of how the meter works. This is a completely separate issue from the pH truly being lower at higher temperatures, which ATC doesn't correct for anyway.

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Mash temp = 150-ish F
Max ATC testable temp (on most meters) = 120-ish F

So the mash pH will be more acidic at 150F than 120F. Is there a consistent way to calculate the pH change caused by the temperature shift of cooling your sample to a testable temp?

Or, alternatively, is the change enough to matter? If we're talking like a -0.01 pH change, that's too small to care it seems.

The shift depends on the mash. DeClerck had data for a soft water and hard water mashes. The slope of the former was about 0.0071 pH/°C whereas the shift for the latter was about 0.0077 pH/°C. These slopes imply substantial (0.2 - 0.3) shifts in pH from room to mash temp.

It is important to take readings at room temperature because everyone is now standardizing on that practice but, more importantly, to prevent thermal stress to the electrode. Third is that room temperature measurements put less demand on ATC so that if the isoelectric point is out of spec it won't lead to big innacuracy. It is handy to be able to do the cal without worrying about temperature. If you stay close to room with the sample you don't have to worry about temperature there either but I do advise writing the temperature down with the pH reading when you record the data.

From http://www.all-about-ph.com/ph-measurement.html:

Solution temperature compensation

If you want to compare pH values measured at different temperatures you need to use a function called solution temperature compensation. Solution temperature compensation converts the pH at the measurement temperature to the pH at a reference temperature. The reference temperature is almost always 25°C.

Note:
Do not confuse solution temperature compensation with the automatic temperature compensation used to correct the pH electrode, see at the beginning of this page.

The change in pH with temperature is called the solution temperature coefficient (pH/°C). For example, if a solution has a temperature coefficient of -0.035 [pH/°C], the pH decreases 0.035 units for every °C increase in temperature. Usually the temperature coefficient must be determined empirically.

ajdelange said:

These slopes imply substantial (0.2 - 0.3) shifts in pH from room to mash temp.

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So what I'm hearing is that we pay a bunch of money for an accurate pH meter, then still have to ballpark the adjustment from room temp to mash temp pH (because all we care about in this instance is mash temp pH), unless we manually calculate the solution temperature coefficient for each mash?

Using DeClerck's solution temperature coefficient for soft water:
Room temp = 25C
Mash temp = 65C-70C
pH compensation for 65C = 0.284
pH compensation for 70C = 0.3195

I think it's clear but just in case it isn't, what you are calling "solution temperature compensation" represents a real change in the pH i.e. the hydrogen ion concentration caused by change in acid pK's (related to the energy it takes to wrest a proton away from an acid). ATC does not compensate for this. It compensates for the electrodes change in response to a given pH as a function of temperature. Perhaps an example: Suppose a mash has pH 5.2 at 20 °C. The pH meter's response will be -58.167*(5.2-7) = 104.7 mV (assuming the electrode is perfect WRT offset an isoelectric pH) because the "slope" of the electrode is -58.167 mv/pH at 20 °C. If the temperature of the same mash is raised to 50 °C the electrode response will be -64.120*(5.2 - 30*0.0075 - 7) = -64.120*(4.975 - 7) = 129.84 mV. IOW the voltage is higher from 2 effects: real change in pH (to 4.975) and greater sensitivity to change at higher temperature (64 mv instead of 58 mv per pH). It is the job of ATC to calculate the Nernst coefficient (58.167 mV at 20 °C) at the temperature of the sample and divide the electrode voltage by that coefficient to obtain the pH estimate. If a meter without ATC assumes the 20 °C value for all displayed readings (it has to assume something) it would report the pH in the second case (pH = 4.975) as 7 - 129.84/58.167 = 4.778.

bopgun23 said:

So what I'm hearing is that we pay a bunch of money for an accurate pH meter, then still have to ballpark the adjustment from room temp to mash temp pH (because all we care about in this instance is mash temp pH), unless we manually calculate the solution temperature coefficient for each mash?

Click to expand...

We don't really care about pH at mash temperature (unless we are enzymologists). What we care about is something we can repeatedly measure accurately which we can use to predict and thus control the brewing process. Room temperature pH qualifies. In anything written in the professional literature today you can assume that published pH values were measured at laboratory temperature. In DeClerck's books, all pH values were measured at laboratory temperature.

AJ mentions standardization and this is pretty much the key. Do we really know the 5.2 was determined at mash temperature or at room temperature? 5.2 probably isn't a magical number for every brew. Also mentioned by AJ. What we are doing here is forming a common knowledge base to help each other improve our brewing techniques. Certainly there is a range where we simply won't taste the difference.

I poked around and found a formula for temperature correction once and it had more variables than I had inputs for. If you really want to sweat small details you can join us on the telescope makers list where we measure things in fractions of a wavelength of light.

Quick edit. Obviously I was composing as AJ was posting. Not trying to be a parrot.

ajdelange said:

We don't really care about pH at mash temperature (unless we are enzymologists). What we care about is something we can repeatedly measure accurately which we can use to predict and thus control the brewing process. Room temperature pH qualifies.

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Hurrah! AJ and Hermit, you gave me the answer I need.

I definitely don't want to sweat the small stuff. But I felt like I saw a gap in the testing methodology and wanted to understand it. I'm trying to get my head around all this new information before investing in the equipment. I apologize for belaboring the point.

Cheers, y'all.

I pulled the trigger and couldn't be more satisified. I have been following AJ's recommendations and am learning a lot about PH. GET THE METER AND DONT LOOK BACK! If your the type that doesn't want to know the Why's then don't bother. Me personally, I need to know why things come out the way they do so I can make adjustments.

Just to support A.J.'s points, I have studied the 5.2 stuff and its behavior in small mash experiments and have not found good evidence that it does what it is supposed to do. Here is a chart that shows the mash pH of 12 pilsner malt mashes done w and w/o 700 mg/l (the recommended dosage) 5.2 buffer in the mash water. These mashes were done at 6 different residual alkalinity values and as you can see the 5.2 does not keep the mash pH near 5.2 or 5.55 (if we assume that the 5.2 is mash temp pH and that there is a 0.35 pH shift). All it seems to do is keep the mash pH from rising too far as residual alkalinity gets really high.




Kai

Someone here (I think) posted about a call to 5 Star in which he was told that it isn't supposed to get the pH down to 5.2, its supposed to keep it from going below 5.2. I've never checked it from the other direction but if it doesn't have much buffering capacity at 5.2 I guess I don't see that the performance would be much better for that purpose.

From their web site: "5.2 is a proprietary blend of buffers that will lock in your mash and kettle water at a pH of 5.2 regardless of the starting pH of your water."

http://www.fivestarchemicals.com/breweries/homebrewing/products/

It appears that Five Star should rename the product: "5.8 Stabilizer" since that is the only effect it appears to produce. Very disappointing result. Thank you, Kai for investigating this.

I can only assume that Five Star was referring to the pH at mashing temperature, but even in the best case, that temperature shift would be 0.35 units and Kai and AJ indicate that even that shift is a stretch.

With only a little education, any brewer can learn to use acidification to produce better beer. There are several programs that help out with that, including Bru'n Water.

I really like Five Star and their products, but this is clearly one product to view skeptically.

Hermit said:

From their web site: "5.2 is a proprietary blend of buffers that will lock in your mash and kettle water at a pH of 5.2 regardless of the starting pH of your water."

http://www.fivestarchemicals.com/breweries/homebrewing/products/

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The poster did note the discrepancy between what is on the package and website and what this bloke told him.

My interest in 5.2 is very mixed. It may be the only brewing thing I investigated which I think has no relevance to practical brewing. It’s purely the interest that brewers have in this product and it’s apparent inability to live up to the claims made by the manufacturer that caused me to slide it into the mash pH experimental effort. Especially after A.J. has repeatedly said that it shouldn’t be able to work.

Like Martin I stand behind StarSan, another FSC product, which I think makes brewing much easier by providing a stable reusable sanitizer. 5.2 however seems like a desperate attempt to use (buffer) chemistry to solve the problem of incorrect mash pH. Oddly enough, it is primarily marketed to professional brewers who I think should all have at least a basic enough understanding of mash pH so they can adjust it with more conventional methods. They even have the benefit of brewing the same few beers over and over and with a small investment into a pH meter and GH&KH water test they should be able to dial in their water treatment w/o having to know the chemistry behind it. Those tools are likely cheaper than a Bucket full of 5.2 mash buffer.

I meant to contact FSC about this, but in all honesty I don’t even know how to start the conversation so I get a genuine answer.

Kai

I've often wondered why a firm with an otherwise excellent reputation would sully it by selling a product which doesn't work and they must know it doesn't work - all it takes is a pH meter. Interstingly enough a citric acid based buffer should work (it has a pK of 4.77 and so is compliant with the rule of thumb. The obvious concern is with how much it takes to overcome the buffering capacity of the malt (and water) and whether that's sufficient to make the beer taste citrusy (without the use of US hop cultivars).

If you look back at your really old homebrewing books you will find many recipes called for a citric acid addition.

As for the pros - I'm sure Anheuser Bush has inorganic chemists on staff to worry about such things but we as homebrewers seem to worry much more about water chemistry than the professionals. I got agreement to that statement from one group of 3 pro's (who work for a rather large and well known chain) and another guy really doesn't worry about it at all other than adding a little gypsum to ales because he was taught (by Michael Lewis) that one's water is one's terroir I even gave this gentleman a pH meter when he opened and told him I'd be happy to come back and take some measurements on a brew day. I'm still waiting for that call.

OTOH Sierra Nevada measures pH, alkalinity, and the hardnesses every day. I presume they also check mash and beer pH from time to time.

Kaiser said:

My interest in 5.2 is very mixed. It may be the only brewing thing I investigated which I think has no relevance to practical brewing. It’s purely the interest that brewers have in this product and it’s apparent inability to live up to the claims made by the manufacturer that caused me to slide it into the mash pH experimental effort. Especially after A.J. has repeatedly said that it shouldn’t be able to work.

Like Martin I stand behind StarSan, another FSC product, which I think makes brewing much easier by providing a stable reusable sanitizer. 5.2 however seems like a desperate attempt to use (buffer) chemistry to solve the problem of incorrect mash pH. Oddly enough, it is primarily marketed to professional brewers who I think should all have at least a basic enough understanding of mash pH so they can adjust it with more conventional methods. They even have the benefit of brewing the same few beers over and over and with a small investment into a pH meter and GH&KH water test they should be able to dial in their water treatment w/o having to know the chemistry behind it. Those tools are likely cheaper than a Bucket full of 5.2 mash buffer.

I meant to contact FSC about this, but in all honesty I don’t even know how to start the conversation so I get a genuine answer.

Kai

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Well, I would do it in writing only. Simply point them to your experiments and ask them if they can suggest why they don't line up with their claims. The ONLY thing I could think of is that their claim is to lock in the "water". They just neglect to point out that it is useless once you add the grain.