Cheap Ph Meter Vs. $100 Ph Meter Test

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A sodium bicarbonate solution has a pH of about 8.3
This may be a dumb question, but wouldn't the pH of that solution depend upon the water it was mixed with, and the concentration of the solution itself? Please note that I'm not trying to stir up any shite, but just questioning something that seemed like a illogical generalization to me. Educate me, please?
 
This may be a dumb question, but wouldn't the pH of that solution depend upon the water it was mixed with, and the concentration of the solution itself? Please note that I'm not trying to stir up any poopye, but just questioning something that seemed like a illogical generalization to me. Educate me, please?

Sodium bicarbonate (actually, any bicarbonate ) is a buffer. The concentration of the solution and the pH of water you started with will affect the pH of the solution a little, but not much. The bicarbonate buffer should overwhelm whatever else is in the water; for the most part, anyway.
 
My experience with what I consider a more expensive meter (given my brewing means) seems more akin to what some folks are recounting for the cheapies. I bought a Milwaukee pH56 and treated it per the manufacturer's guidance. The electrode wasn't even stable enough to calibrate.

I'm currently using a cheapie to measure mash, sparge and wort pH, and it seems to be stable enough when I check it with buffer solutions. I'm not comfortable with good enough, but am wary of putting money into something that doesn't result in much better.

That said, and having read this thread, I'm going to give a better meter another shot. I'm willing to believe that my experience is unusual, even though the particular meter I initially chose was probably not a good buy.

Thanks all for the info.
 
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This may be a dumb question,
Not a dumb question at all.

but wouldn't the pH of that solution depend upon the water it was mixed with, and the concentration of the solution itself?
Yes, it would. I assumed that if one were going to do a check on a pH meter with a sodium bicarbonate solution (which he would only do in desperation because it's not a good buffer but it is in everyone's kitchen) that he would want the solution to have pH 8.3 and that he would, therefore, mix the sodium bicarbonate with DI or at least RO purified water or, assuming that he had neither of those, make a strong enough solution that the bicarbonate would swamp whatever was in the water. For example, a couple of teaspoons full in a quart or less of water. But yes, if the water has high alkalinity and a low pH and only a little bicarbonate is added to it it could easily pull the pH away from 8.3 by at least as much as you observed.
 
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Sodium bicarbonate (actually, any bicarbonate ) is a buffer. The concentration of the solution and the pH of water you started with will affect the pH of the solution a little, but not much. The bicarbonate buffer should overwhelm whatever else is in the water; for the most part, anyway.
There seems to be a lot of confusion about what buffering is and what a buffer is. Buffering is the amount of acid or base required to induce a small pH change. A solution that requires a lot of acid for a small pH change is said to have high buffering capacity. A solution in which the pH changes quite a bit when only a small amount of acid or base is added is said to have weak, little or poor buffering. The nuance come in the fact that solutions with mixtures of the ions of an acid have pH regions where buffering is strong and others where it is weak. Though such a solution has buffering at any pH if we want to use it as a buffer, i.e. something that holds pH, we must add acid or base to get it to the pH (or one of the pH's) where buffering is strong. Thus we can call a mix of carbonic acid and bicarbonate ions a buffer when the mix is such that the pH is 6.38 and we can call a mix of bicarbonate ions and carbonate ions a buffer when the pH is near 10.38 (and do - this is the blue buffer furnished with many pH outfits) but we cannot call a solution of straight bicarbonate ions in water a buffer because it exhibits near 0 buffering capacity at its native pH of 8.3.
 
I use a Ysi at work every day that measures ph, temp, do, orp, and conductivity. Calibrate 2 times a day. This is a top of the line professional piece of equipment. And it drifts pretty regularl. If you are within 0.05 of your 5.2, you're doing great. Look up your states tolerances for ph in drinking water ,for example .Can be a loose tolerance. Fyi

Edit: should have said I check calibration twice a day
 
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5 hundredths is pretty dang good in my book. I'll take that all day and 4 times in Tuesday. I am a simple brewer, though.
 
5 hundredths is pretty dang good in my book.
That's probably because you don't appreciate the significance of what accuracy of 0.05 implies. That number is the standard error associated with a measurement. If you read 5.40 with a standard error of 0.05 that means that there is a 68% chance that 5.35 < pH < 4.05 and a 99% chance that 5.3 < pH < 5.4. That is not good enough to be able to positively detect the kinds of changes one would expect to see in a mash pH by, say, varying the amount of a dark crystal malt by a few percent. With a good meter you can easily achieve ± 0.02 (or even a little better) with ±0.02 buffers in which case the probable ranges become 68% chance that 5.38 < pH < 4.02 and a 99% chance that 5.36 < pH < 5.44. Not as good as we would like, of course, but appreciably better.

OTOH if you are happy with 0.05 you are happy with ±0.05. I don't object to that. What I do object to is a post that implies that other brewers should accept ±0.05 with the implication being that it is adequate.
 
I'll kind of agree with AJ here. In summation:

As a scientist, 0.05 accuracy is not good enough. As a homebrewer, 0.05 is good enough... unless you're also a scientist.
 
That's probably because you don't appreciate the significance of what accuracy of 0.05 implies. That number is the standard error associated with a measurement. If you read 5.40 with a standard error of 0.05 that means that there is a 68% chance that 5.35 < pH < 4.05 and a 99% chance that 5.3 < pH < 5.4. That is not good enough to be able to positively detect the kinds of changes one would expect to see in a mash pH by, say, varying the amount of a dark crystal malt by a few percent. With a good meter you can easily achieve ± 0.02 (or even a little better) with ±0.02 buffers in which case the probable ranges become 68% chance that 5.38 < pH < 4.02 and a 99% chance that 5.36 < pH < 5.44. Not as good as we would like, of course, but appreciably better.

OTOH if you are happy with 0.05 you are happy with ±0.05. I don't object to that. What I do object to is a post that implies that other brewers should accept ±0.05 with the implication being that it is adequate.
Don't include me with your we.

I keep things simple . Stressing over hundredths of a SU here or half a degree in temperature there is not conducive to a happy brew day for me. It's peanuts.

And your post implies other brewers should not accept 0.05

But you do you and I'll do me.
 
Stressing over hundredths of a SU here or half a degree in temperature there is not conducive to a happy brew day for me. It's peanuts.

I agree that the ultimate result is peanuts. Managing pH to within about 0.1 unit is good enough for most people.

But being able to discern active variation in pH to 0.01 units during the measurement phase is still helpful. 0.05 resolution is probably not good enough then.
 
If I had a palate that could taste the difference 0.01 SU makes, I'd probably concern myself with it.

I am not lucky enough to be one of those folks
 
Nor, apparently, fortunate enough to be among those capable of understanding No. 91. If you are unable to taste the difference between beers mashed at pH's 0.05 or 0.1 pH apart that is sad but I'm sure there are still many beers you can enjoy. But my job here isn't to try to convince those at your level of understanding or palate sophistication (or anyone, really) but rather to see to it that those who do have fuller abilities have the information they need to make informed decisions.
 
As a homebrewer, 0.05 is good enough...
Perhaps. But, as shown in No. 91, you really need a meter with standard error of ±0.02 or better to be more than 90% certain that you are within ±0.05 of what the meter reads.

Also note that not all of home brewing is making beer for consumption. Some of us try to give something to the hobby by researching various aspects of the science and practices, publishing spreadsheets etc. Measurement of pH is often involved in the underlying investigations and those investigations wouldn't be worth much if we couldn't measure to ±0.02 or better.
 
Would more precision change technique or process? In other words, if more precision causes more or less ion/acid additions then it may be worth the investment. Would +/- 0.05 pH be a significant amount of any ion/acid? I'm always as "precise as possible" and if I can be more precise I go down that road. OTOH several people I know don't know the meaning of the word and live in utter chaos. Both worlds seem to get along just fine, both have just as much stress, and they seem to balance each other out.
 
No, a change in pH doesn't necessarily imply an addition of more or less acid. It is more like a temperature. Beer mashed at proper temperature and pH tastes better than beer mashed at other pH and temperature. For most people, there is a dramatic difference in flavor profile when mash pH is varied by a couple of tenths. There should be a less dramatic difference between differences of 0.1 pH unit and less dramatic still for a change of 0.05 but it should be noticeable. I emphasize again that to control pH to ±0.05 with certainty requires a meter with accuracy ±0.02 as many don't seem to grasp that point. Though few if any explore it there should be a 'best' mash pH for a particular beer. In order to find that pH a brewer would try several mash pH's spaced, say, 0.05 pH but in order to do that he will need to be confident that mash #2 is really 0.05 pH less than mash #1 or, put another way, that the lower reading he observes is really because of lower pH and not because of electrode drift.
 
Perhaps. But, as shown in No. 91, you really need a meter with standard error of ±0.02 or better to be more than 90% certain that you are within ±0.05 of what the meter reads.

Also note that not all of home brewing is making beer for consumption. Some of us try to give something to the hobby by researching various aspects of the science and practices, publishing spreadsheets etc. Measurement of pH is often involved in the underlying investigations and those investigations wouldn't be worth much if we couldn't measure to ±0.02 or better.

You want to turn everything into the CRC Handbook of Chemistry and Physics? Go right ahead, I won't stop you. I'll even use your data if it interests me.

But most of us here just don't need that level of awesomeness.

I'm willing to bet 200 gallons of beer that blind triangles of >20 beer aficionados cannot reliably with 95% confidence taste the difference in two otherwise identical beers when mashed at a pH of say exactly 5.40 vs. exactly 5.45, measured with the one of the best calibrated pH meters in the universe. Assuming my theory could be proved true and reproduced and confirmed by many, then... why should anyone but scientists in a laboratory waste time and money on purchase and use of pH meters good to +-0.02?

All the nitty gritty science, technology, and math in the world doesn't matter if we can't taste differences. In the end, we here are all brewing beer, with the goal that it be consumed and enjoyed. Taste of the final beer is the bottom line. Maybe this pH stuff matters a little. Maybe swings of 0.10, 0.20, or 0.30 are what really matter when it comes to final beer quality -- I am not certain of the exact taste threshold and actually I would be interested to find out what that threshold is. But, if taste is indistinguishible either way at +-0.05, then sharpening the tool to +-0.02 does not matter in the slightest with respect to the bottom line. To a scientist, perhaps. To anyone else on the planet, no.

This all seems to be also a form of analysis-paralysis and over-thinking. I fall victim to this myself too often. Perhaps it is time to recognize what is happening, and just let it all go. Maybe I won't even measure my mash pH anymore. I'm not convinced that it matters in the slightest. I brewed all-grain for about 10 years without major issues until I started measuring mash pH. Has my beer gotten any better since I started measuring? I really don't think so. So then, am I just wasting my time?! My current answer = Probably!

Cheers.
 
But most of us here just don't need that level of awesomeness.
Yes, but some do and it is to them I write and for them I do the research. I fully realize that much of what I post is meaningless to those with limited understanding but remember that this forum is for "In depth technical threads related to the biology and chemistry of home brewing"


...why should anyone but scientists in a laboratory waste time and money on purchase and use of pH meters good to +-0.02?
Because it isn't a waste of time or money. All but the cheapest meters meet that level of performance now. You have to look at the Chinese toy meters to find one that isn't that good these days. I guess you can still find old stock of meters from the days of yore out there though.

All the nitty gritty science, technology, and math in the world doesn't matter if we can't taste differences.
Where the heavy research is done is in the large breweries where the object is not your taste perception but to increase profits largely through increased sales which is, presumably, effected by the way the product tastes. You can be sure that these breweries have thoroughly researched pH (and every other variable they can think of) with the object of finding ways to increase sales.

In the end, we here are all brewing beer, with the goal that it be consumed and enjoyed. Taste of the final beer is the bottom line.
As noted in an earlier post there is a great deal more to it than just this for many home brewers. The fact that you are unaware of these other aspects does not mean that they aren't important to some and you should be grateful to those people as much of the techniques that allow you to make decent beer were discovered by those guys.

Maybe this pH stuff matters a little. Maybe swings of 0.10, 0.20, or 0.30 are what really matter when it comes to final beer quality -- I am not certain of the exact taste threshold and actually I would be interested to find out what that threshold is.
For someone who is 'not quite certain' you seem to be quite strongly convinced that mash pH isn't that important, as you later state.


But, if taste is indistinguishible either way at +-0.05, then sharpening the tool to +-0.02 does not matter in the slightest with respect to the bottom line. To a scientist, perhaps. To anyone else on the planet, no.
It is the scientists (and advanced home brewers too, in fact), aware of things that you clearly are not, who have, and will continue to bring about the material and process improvements that allow you to make beer as good as you can today.
I'm not convinced that it matters in the slightest. I brewed all-grain for about 10 years without major issues until I started measuring mash pH. Has my beer gotten any better since I started measuring? I really don't think so.
Unfortunately, the only conclusion one can draw from this statement is that your palate is impaired, somehow, relative to the normal taster's. A normal drinker, at least one with some training in beer tasting such as a BJCP judge, would have noticed profound differences. I often quote "All the flavors just became brighter." as an example of the response from those undertaking mash pH control for the first time. I number myself among the many that found tight control of mash pH to be one of the most dramatic things I have done to improve my beer (with the other being temperature controlled cylindroconical fermentation).



So then, am I just wasting my time?! My current answer = Probably!
Yes, given your palate impairment, I am afraid you are. I am color blind. If I spend money on a TV set with widened gamut I am wasting that money (and the time taken in trying to set it up). Given that you can't taste the improvements brought about by mash pH control why waste time trying to implement it? Consideration for other people who drink your beer, I suppose. Whether you can taste the difference or not your beers are better when mashed with a pH between 5.4 and 5.6. Though you can't tell, your 'customers' will be able to. Just as I use electronic tools to color correct my photos/videos against things I can't see for the sake of people I show them too I think it is sort of incumbent on you to use an electronic tool to make corrections you can't taste to insure that those who drink your beer are getting decent stuff.
 
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My palate impairment, if I have one, is irrelevant. I would ask anyone with real blind triangle data for the experiment I have proposed to present that data. Can >20 blind, BJCP trained & qualified aficionados really taste a difference in a beer mashed at pH 5.40 vs. 5.45? Until I see that data, I will not be convinced that any of this matters much, regardless of the quality of my own palate.
 
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Time to put an end to the two person argument, since it was starting to get personal. You've both made your arguments, so there is no need to repeat them over and over.

doug293cz
HBT moderator
 
I would like to hear AJ's comments on that Hanna meter with (IIRC) .01 precision and 0.2 accuracy. Does the hundredths digit even mean anything? I expected better from Hanna, although maybe I shouldn't at that price point; perhaps it's a bargain for $40. Or maybe I don't understand the relationship between precision and accuracy as well as I think I do.

Thanks.
 
My understanding is that .01 precision means that two or more measurements would be within +/- .01 of each other. The .2 accuracy means that each mash pH measurement would be within +/- .2 of the actual mash pH.

For $40 it's not bad, but Hanna does make better for a price.

I've always sought after meters with +/- 0.01 accuracy or better. Been drooling over this one for a while.
 
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I had one of the yellow pH meters and part of the LED on the tenths digit went out. So, 6 and 8 look the same and 5 and 9 look the same. So if my pH happened to be more than 5.49, I had almost no idea what it was. I ended up buying a MW-102. It may have been covered earlier in the thread, but component quality factors in also.
 
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