pH meter recommendations?

[kincade]

Hanna Temp/PH pen for $69.95 with free shipping is hard to beat!

Hanna HI 98127 pH Tester - Mitchell Instrument Company

Is there any advantage to ordering with the 'NIST' calibration certificate for $13 more?

 

[mabrungard]

I'm not sure what NIST calibration would do for you with a pH meter. That might be valid for a short while. But as the probe ages, the calibration goes out the door. You really have to perform calibration checks on a daily basis to make sure that the meter electronics haven't shifted and the probe chemistry and function is still correct.

 

[ajdelange]

Is there any advantage to ordering with the 'NIST' calibration certificate for $13 more?

What does 'NIST' stand for? Nice Idea for Skinning the Turkeys? I'd stay away from this outfit. I have never seen NIST calibration offered for a pH meter and to even suggest such a thing for a device with 0.1 pH specified accuracy seems a cruel joke. And I can't imagine what it would even mean. A pH meter is basically a sensitive volt meter but one doesn't need to have an absolute voltage calibration on the thing because the user must calibrate it himself before every use. It is recommended that he use NIST traceable buffers and so I can only imagine that it means they do a calibration using NIST buffers before shipping which would be worthless because you would have to recalibrate it yourself the first time you used it.

 

[ryclo]

NIST stands for National Institute of Standards and Technology. Its third party proof that the tester is meeting the accuracy claims by the manufacturer. If you are an ISO9000 facility you are required to have this on any equipment you use, if you dont know what it is you do not need it as it does not do anything to the accuracy of the instrument.

 

[ajdelange]

That's not true. I don't know what the NIST calibration standard calls for but I would assume that a check on the accuracy/linearity of the RTD and a check on the linearity of the A/D are involved (offset isn't so important here because that would get calibrated out). Both of those effect the accuracy of pH meter readings. But on an 'instrument' with an 0.1 pH accuracy spec?

[Edit] Another thing I'd really like to see verified is the isoelectric pH of electrodes. I wonder if they do that in NIST certification (of real meters which costs about $150 - not the ridiculous $19 'NIST certification' for the $69 meter). The reason I'm hard over on it is that I once bought an expensive electrode that had an isoelectric pH way out of spec. The electrode is perfectly useable (I've had it for years) but I have to do cal/pH/ATC in my own software which works with arbitrary pHi.

 

[jfrizzell]

How do you feel about an $83 NIST cert on a $75 meter?

http://www.mitchellinstrument.com/hanna-hi-98127-phep4-ph-tester.html

 

[ryclo]

If you are worried about accuracy, you would not buy a $75 ph meter in the first place. NIST traceability is simply comparing the readings of the ph meter to a calibration standard (this standard is traceable all the way back to the gov't NIST labs) and verifying that the instrument is as accurate as the specs say its supposed to be. There is no standard accuracy that the NIST labs say all PH testers must meet. A NIST cert is not a calibration of the device.

 

[the_bird]

Yoop, did you end up getting that Milwaukee 56? How do you like it? Seem to work well for you?

 

[Yooper]

Yoop, did you end up getting that Milwaukee 56? How do you like it? Seem to work well for you?

Well, I like it, in that it's easy to use. But I have had some troubles with it. They've replaced the electrode twice, and I sent it in once to them. They haven't charged me, but it came back last week and I used it. I calibrated it, and within a couple of minutes it was drifting again, pretty badly. I calibrated it again, and it seemed ok then. If I had it to do over, I would have chosen a different meter.

 

[the_bird]

I was thinking about buying one, but I'm not sure how much of an improvement it would be over the ColorpHast pH strips I have now. I know Kai's done some work showing that the strips aren't all that accurate, but I'm not sure if any of the meters in this price range are much better.

 

[Yooper]

I was thinking about buying one, but I'm not sure how much of an improvement it would be over the ColorpHast pH strips I have now. I know Kai's done some work showing that the strips aren't all that accurate, but I'm not sure if any of the meters in this price range are much better.

Oh, I'm glad I have one don't get me wrong. I've used it, and really had a chance to see what the pH does with my water, RO water, etc. Kai's spreadsheet is pretty accurate in predicting mash pH, but I mostly use Brunwater now (they seem to give me the same predictions).

I've also used it to check the pH of our garden soil, and will use it sometime to check the pH of my soaps. I'm sure I just got a lemon with the first two electrodes, but like I said even the other day it drifted right away after the first calibration. I think that it's far more accurate than the strips, plus easier to read. Colors are hard to see!

 

[ajdelange]

Yes, they are better. BTW I just found out, from a web ad, that pHep stands for 'pH electronic paper' which implies that the accuracy of this series is comparable to test papers but as Kai and others have confirmed strips perform unusually poorly in the brewing environment for whatever reason. After considerable pondering as to how it is possible to build electronic meters which perform so badly and some experimentation I conclude that the answer is not in the electronics at all but in the electrodes. Inexpensive ones tend to be subject to drift after only a few minutes. Yooper's experience is supportive of this notion. In the pH Calibration Sticky steps are listed which you can use to check on the stability of your meter. Essentially you calibrate it and then read one of the cal buffers (prefferably 4) over a period of time. The meter should consistently read 4 plus or minus a couple of hundredths. If readings are erratic or show a trend over time then you have a problem with the electrode. If the drift is slow i.e. it reads 4.00 just after calibration and 4.10 after an hour you can still use the thing simply by recalibrating frequently. This is, of course, a PITA and what kind of performance you get determines how much of a PITA it is.

These meters are a lot better than they used to be but they are not great. Knowing what pHep stands for should put things in perspective. Unfortunately I don't have a solution other than the one I often offer which is to see if you can come up with a good used meter and buy a good electrode for it. I know 2 commercial brewers who got good meters as gifts from laboratories that were upgrading and in one case the guy is still using the electrode that came with it. I don't think the other guy has ever used his but you will probably have to buy a new electrode and the odds of finding a benefactor are small so a Craig's list or Ebay buy is the more likely route. A good electrode will cost you over $100 but the new electrodes are fantastic in that they are good for years - not a year or less as they were only a few years ago.

 

[Homercidal]

I bought the Hanna pHep5 and used it a couple of times to verify my spreadsheets. The problem I have is forgetting to use it on brew day! I haven't had any issues with mine, but I've been off my calculations two of the three times I've brewed. So I haven't really pinpointed where the difference enters into. Could be my actual water makeup on that particular day (tap vs RO with campden, etc.) The meter was off by about 2 points from my calculations. Off one direction one time, the other direction the other.

I am glad I have it, and if I can only remember to use it I'd have more to report. I think if you are serious about water, then it's a great tool to have.

 

[the_bird]

Yeah, I think my experience at Kai's house might have triggered some of his experiments with the pH strips; I took a mash reading with the papers that indicated I was in-range, but his check with his (properly calibrated) meter showed that I was off by a considerable degree, I had been asking him for potential theories on why my efficiency has been so poor, which is why we started checking my pH in the first place. So, I know the strips suck, it's just a question in my head of whether a $70 pH meter is going to suck just as bad.

 

[Yooper]

Yeah, I think my experience at Kai's house might have triggered some of his experiments with the pH strips; I took a mash reading with the papers that indicated I was in-range, but his check with his (properly calibrated) meter showed that I was off by a considerable degree, I had been asking him for potential theories on why my efficiency has been so poor, which is why we started checking my pH in the first place. So, I know the strips suck, it's just a question in my head of whether a $70 pH meter is going to suck just as bad.

In short, no. The $70 meter doesn't suck. I just had some issues with the electrode(s). However, their customer service is top notch (Milwaukee Instruments) and they talked to me on the phone immediately when I called, replaced the electrode twice, and even had me send the whole meter in to be checked.

I feel like I got $65 worth, for sure, probably more- because the beer is better, my water treatment is dependable, and I am making notes on repeat recipes on the actual pH. I feel like I"m far more comfortable with predicting the probably pH, and using the spreadsheets, as well as falling into the "less is more" camp. The only thing I meant was that I might have chosen a different meter.

 

[Dog House Brew]

So does Brunwater end up predicting your ph when checking it with your meter? I got a meter at the same time and it is still in the box. I just started looking at Brunwater and wondered about the accuracy. Was using EZ water before, but had no way of checking the accuracy. After reading about Yoop's issues it deterred me from using the meter.

 

[ajdelange]

So does Brunwater end up predicting your ph when checking it with your meter?

It, as do the other spreadsheets, predicts pH any time you put numbers about water and grain into it.

I got a meter at the same time and it is still in the box.

Don't understand this. At the same time as what?

I just started looking at Brunwater and wondered about the accuracy. Was using EZ water before, but had no way of checking the accuracy. After reading about Yoop's issues it deterred me from using the meter.

You are right to question the accuracy of both the spreadsheets and the meters and the papers. Without even going into the questions that must be asked before discussing accuracy I think it is safe to say that the papers are the least accurate and the meters, provided they are properly used and not defective, are best with the spreadsheets and calculators in between. But this is a bit of an apples and oranges comparison as meters and papers both measure pH and spreadsheets and calculators attempt to determine them based on models. Models are imperfect but so are measurements. A measurement is ultimately better than a prediction provided that one has confidence in the measurement. With a meter it is possible to attain that confidence by doing the stability check I've described earlier and in the pH Calibration sticky. If you can't pass the stability check then you have limited confidence in your measurement and will have to rely on the prediction of the spreadsheet or calculator (or,if you have been doing this long enough, your experience).

Of course one may have confidence in a model. But how is this obtained? By collecting a large set of measurements in which one has high confidence. There is the additional requirement that the measurements span the range of conditions over which the model purports to apply. It is, of course, difficult or nearly impossible to achieve this goal and so the models are adjusted to fit the experiences of the modelers or the modelers and their friends (where a friend is defined as anyone who gives the modeler feedback). Thus you will find in these pages people who say A's version tends to give low pH predictions and B's version high, or conversely. It often depends on the kinds of beer the poster tends to brew.

You should at least try out your meter. As is the case with any new technology (new to you - pH meters have been around for a while) there is a learning curve. Get the thing calibrated and go around the house (mostly the kitchen) measuring the pH of milk, water, lemon juice, soda..... to gain familiarity. Do the stability check. Then move on to brewing applications but be sure to do the stability check after each set of readings while brewing until you are confident (or not) in your meter.

 

[Yooper]

You should at least try out your meter. As is the case with any new technology (new to you - pH meters have been around for a while) there is a learning curve. Get the thing calibrated and go around the house (mostly the kitchen) measuring the pH of milk, water, lemon juice, soda..... to gain familiarity. Do the stability check. Then move on to brewing applications but be sure to do the stability check after each set of readings while brewing until you are confident (or not) in your meter.

One thing that I have done is compare EZ water, Brunwater, and Braukaiser's predictions with my own pH meter.

Brunwater and Braukaisers are normally the same, but EZ water is always lower. On my last brewday, Brunwater predicted 5.6, and I got a mash pH of 5.52. Pretty darn close! EZ water has been off, often by .2 or more, but sometimes not as much.

The brewdays before that, my actual pH was a bit lower than Brunwater predicted, but not terribly. They were also pretty close, at least close enough that I didn't do any adjustments on the fly.

So, I'd say the spreadsheets that work for you do help- based on my experiences. I'd bet that EZ Water works for others, while Brunwater works better for me.

 

[Dog House Brew]

I'm glad to hear that Brunwater is so close for you Yooper. Our water is very similar and my results should be close. I will work with my meter. I just wanted to know that the spread sheets were close enough while trying to use my meter. I can see the advantages of having a meter for sure. Nice to have the experts here that chime in and really help with the water as well as the use of the hardware.