Author Topic: pH probe failing too often  (Read 603 times)

Offline HighVoltageMan!

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pH probe failing too often
« on: March 22, 2018, 05:30:42 PM »
I was brewing this weekend and once again my pH meter wouldn't calibrate. The probe 3-4 months old, I'm sick swapping out my probes. They are handled with kit gloves, stored in the proper solution, cleaned occasionally with the proper solution and I still have a high failure rate. I have a Milwaukee PH56, the probes are @ $40 with shipping.

So I did some research and found that if I use a double junction pH probe, my probe life would be extended. It seems that the probes that come these cheaper "pocket" meters are single junction and are not intended to be used on "food" or any other liquids that contain a lot of proteins and particulates, but double junction probes fair better. The other probe I ran across was an ISFET, which uses a FET junction to measure pH, but I have no idea if this is a longer lasting probe or if it is well suited to wort/beer.

Has anyone looked into this and do you have any info on the best probes for wort/beer? I was looking at this pocket meter. It has a double junction probe, looks more promising than what I have.

https://envirosupply.net/shop/water-quality/oakton-waterproof-double-junction-phtestr-30.html?gclid=Cj0KCQjwqM3VBRCwARIsAKcekb0Igz1Q0uymptrp9HbZML2JStBCANILTyBIdaH2k-AeyPWrW-3uAkMaAtntEALw_wcB


Online dmtaylor

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Re: pH probe failing too often
« Reply #1 on: March 22, 2018, 05:58:24 PM »
Hmm.  I've been happy with my cheap $16 meter from Amazon.  As a homebrewer there's no way I would spend $40 a pop on new probes.  If I worked in a laboratory, sure.  But sometimes, good enough is good enough.
Dave

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Online Robert

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Re: pH probe failing too often
« Reply #2 on: March 22, 2018, 06:00:50 PM »
I can highly recommend this meter.  I have had many years of great service.  When I stupidly destroyed one, I got another and have had many more years of faultless service.  Never had to replace a probe.  Remember, never test anything that's not room temperature,  and probes last a very long time.
https://hannainst.com/hi98128-phep-ph-tester.html
Rob Stein
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Offline BitterItDown

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Re: pH probe failing too often
« Reply #3 on: March 22, 2018, 06:53:45 PM »
I've slammed this one around, measuring pH at mash temperatures, no storage solution, cheap calibration solutions, just a generally tough meter that seems to keep on ticking.  Though I do always rinse it before capping it.  Not bad for $14.

https://www.amazon.com/DOY-PH-Hydroponics-0-00-14-00-Measurement/dp/B0711SC1JM/ref=sr_1_1_sspa?ie=UTF8&qid=1521743782&sr=8-1-spons&keywords=ph+meter&psc=1#customerReviews

More expensive solutions are made that have cloth junctions that you can pull out a tad to renew the junction, which helps extend the life of the electrode.  Some even transmit to android/iphone and make pretty graphs, etc...

The halo's are nice (and expensive)
https://hannainst.com/halo-ph-electrode-for-beer-analysis-fc2142.html


Offline HighVoltageMan!

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Re: pH probe failing too often
« Reply #4 on: March 22, 2018, 09:32:48 PM »
I can highly recommend this meter.  I have had many years of great service.  When I stupidly destroyed one, I got another and have had many more years of faultless service.  Never had to replace a probe.  Remember, never test anything that's not room temperature,  and probes last a very long time.
https://hannainst.com/hi98128-phep-ph-tester.html

This one doesn't look bad, but I guess my question is which probe works best with (room temperature) wort. If you read the description of this model it reads "Great for drinking water, aquariums, pools, & ponds", which I read as for use with mostly water. Wort contains a lot of material that plugs up probes and require a more robust probe.

It's pretty common to see probe failure, I just want to maintain accuracy and reliability. I was wondering if anyone can shed light on single junction or double junction probe reliability. From what I read so far, most of the probes people are using for measuring pH in brewing are not the best fit because of the harsh environment.

Maybe the Milwaukee probes just suck, I dunno.
« Last Edit: March 22, 2018, 09:35:54 PM by HighVoltageMan! »

Online Robert

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Re: pH probe failing too often
« Reply #5 on: March 22, 2018, 09:50:08 PM »
I can highly recommend this meter.  I have had many years of great service.  When I stupidly destroyed one, I got another and have had many more years of faultless service.  Never had to replace a probe.  Remember, never test anything that's not room temperature,  and probes last a very long time.
https://hannainst.com/hi98128-phep-ph-tester.html

This one doesn't look bad, but I guess my question is which probe works best with (room temperature) wort. If you read the description of this model it reads "Great for drinking water, aquariums, pools, & ponds", which I read as for use with mostly water. Wort contains a lot of material that plugs up probes and require a more robust probe.

It's pretty common to see probe failure, I just want to maintain accuracy and reliability. I was wondering if anyone can shed light on single junction or double junction probe reliability. From what I read so far, most of the probes people are using for measuring pH in brewing are not the best fit because of the harsh environment.

Maybe the Milwaukee probes just suck, I dunno.
Like I said, I've never had problems over hundreds of batches, and brewing is all I use it for. Popular model sold by LHBS, MoreBeer, and many others.  I think the Hanna blurb is just addressing bigger markets. Mash and wort are hardly harsh environments.  Guys at LHBS say it's used for wine and canning stuff like tomato sauce by buyers without problems, those just may require occasional cleaning of the electrode. They sell a cleaning solution I've never used, just take a quick reading and rinse it off right away.  Instructions don't specify regular cleaning, and they say calibrate monthly, but I find that's overkill.   Again, the biggest cause of electrode failure for homebrewers is taking readings at high temperature,  which gives an incorrectable wrong reading anyway.
Rob Stein
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Offline HighVoltageMan!

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Re: pH probe failing too often
« Reply #6 on: March 23, 2018, 02:39:22 PM »
I can highly recommend this meter.  I have had many years of great service.  When I stupidly destroyed one, I got another and have had many more years of faultless service.  Never had to replace a probe.  Remember, never test anything that's not room temperature,  and probes last a very long time.
https://hannainst.com/hi98128-phep-ph-tester.html

This one doesn't look bad, but I guess my question is which probe works best with (room temperature) wort. If you read the description of this model it reads "Great for drinking water, aquariums, pools, & ponds", which I read as for use with mostly water. Wort contains a lot of material that plugs up probes and require a more robust probe.

It's pretty common to see probe failure, I just want to maintain accuracy and reliability. I was wondering if anyone can shed light on single junction or double junction probe reliability. From what I read so far, most of the probes people are using for measuring pH in brewing are not the best fit because of the harsh environment.

Maybe the Milwaukee probes just suck, I dunno.
Like I said, I've never had problems over hundreds of batches, and brewing is all I use it for. Popular model sold by LHBS, MoreBeer, and many others.  I think the Hanna blurb is just addressing bigger markets. Mash and wort are hardly harsh environments.  Guys at LHBS say it's used for wine and canning stuff like tomato sauce by buyers without problems, those just may require occasional cleaning of the electrode. They sell a cleaning solution I've never used, just take a quick reading and rinse it off right away.  Instructions don't specify regular cleaning, and they say calibrate monthly, but I find that's overkill.   Again, the biggest cause of electrode failure for homebrewers is taking readings at high temperature,  which gives an incorrectable wrong reading anyway.

My guess is that what you describe is is not the norm. Not saying it isn't true, but my experience with pH meters and other test equipment indicates to me that probe failure is not uncommon. My question was to see if someone on this forum were familiar with issue and why it happened, and the best method to prevent this from happening  prematurely. The average life span of a pH probe is any where from 6 months to 2 years depending on the type of probe. This is pretty well documented.

Wort/beer is consider a harsh environment because it contains proteins which clog the permeable membrane on the glass bulb. When this is clog the hydrogen ions are blocked and the meter can't measure the electrical potential between the measured wort (in this case) and the reference solution contained within the probe. Basically, a pH meter is a form of a voltmeter.

I may have answered my own question doing research elsewhere on the web.

1. Dual junction probes are intended to work in a less than ideal environment and are more resistant to the clogging of the membrane. (Maybe)

2. A cleaning solution containing the enzyme pepsin should be used after every use (or brew) to remove any protein that may have collected on the bulb. Rinsing the probe in distilled water is not an effective cleaning method for proteins.

Hanna recommends cleaning regularly with a pepsin solution:

"The HI7073L is a special enzymatic cleaning solution that is specially formulated for use in applications were a pH electrode can be coated with proteins. Electrodes can become dirty from use and will produce inaccurate results even as they read correctly in a pH buffer. Hanna’s cleaning solutions eliminate impurities and residues that are left on electrode surfaces when immersed in samples during measurement and stored incorrectly. Hanna suggests cleaning the bulb and junction of your electrode on a regular basis to ensure that the probe is always clean and prevent any clogging of the junction."

The cleaning solution is fairly cheap ($15.00 for 500mL) and should last a long time.

I don't know if anyone was interested in this, but I found it helpful.

Online Robert

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Re: pH probe failing too often
« Reply #7 on: March 23, 2018, 04:38:42 PM »
Believe it or not my experience is real and I'm not alone.  I follow the directions provided by Hanna with the unit, and it works.  Hence my recommendation.   Maybe I'm just really easy on it, taking quick readings (it stabilizes in a second or two) in room temp samples, and rinsing and storing per the instructions.   I don't doubt that other conditions of use could shorten the life of the electrode.
Rob Stein
Akron, Ohio

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Offline HighVoltageMan!

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Re: pH probe failing too often
« Reply #8 on: March 26, 2018, 03:18:04 PM »
I did more looking into this. It turns out the majority of pH meters use the same basic design. The glass bulb is the reference point and the probe also has a separate membrane for the liquid being measured. The probe life is generally 6 months on the short end and 18 months on the long end, regardless whether or not it's used.

What happens is the membrane get blocked by proteins, organic material and mineral deposits. As this happens the probe response is slower and slower. It may get the point where the probe won't calibrate. This can happen to any gel filled probe, cheap or expensive.

So it can be reconditioned with common household chemicals, bleach and white distilled vinegar.

1. Soak the probe in white vinegar for 10 minutes, the probe should read @ 2.5 pH. This will remove the mineral deposits and soften up the proteins. After the soak, clean with distilled water.

2. Soak the probe for 10 minutes in a 50/50 mix of water and household bleach. This will remove the proteins and kill any microbes that are on the probe(storage solution is an ideal environment for mold growth). The pH measurement should be @ 11.5-12. Clean with distilled water.

3. Soak the probe in the storage solution for at least 2 hours, calibrate. If it fails to calibrate you try this procedure again, but if it still won't calibrate the probe needs replacing.

I did this and my probe came back to life and the response of the meter was almost as fast as new.

I hope this helps someone else.
 

Online Robert

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Re: pH probe failing too often
« Reply #9 on: March 26, 2018, 07:23:43 PM »
Ok HighVoltageMan,  you inspired me to clean my electrode! It still calibrated in a very few seconds (no change) and gives a stable reading in a couple of seconds (no change.)  The reading is also just what I expect in a given wort or beer. So performance clearly was not compromised.  But just to be prudent I'll probably clean it now whenever  I calibrate it.  Thanks for the nudge in the right direction. I still recommend this robust little instrument.
Rob Stein
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Offline HighVoltageMan!

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Re: pH probe failing too often
« Reply #10 on: March 26, 2018, 08:27:40 PM »
Ok HighVoltageMan,  you inspired me to clean my electrode! It still calibrated in a very few seconds (no change) and gives a stable reading in a couple of seconds (no change.)  The reading is also just what I expect in a given wort or beer. So performance clearly was not compromised.  But just to be prudent I'll probably clean it now whenever  I calibrate it.  Thanks for the nudge in the right direction. I still recommend this robust little instrument.

You may have one of those double junction probes, but if I were to buy another pH meter I would choose something different than a Milwaukee PH56. My probe was pretty bad in only 3 months and it shouldn't be that finicky.

Offline mabrungard

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Re: pH probe failing too often
« Reply #11 on: March 26, 2018, 08:51:44 PM »
While I do find that the Milwaukee MW-101 and MW-102 meters are pretty robust and reliable, I've heard plenty of poor stories about the PH56 unit.

As with ALL meters with built-in, proprietary probes, you are stuck with buying the manufacturer's replacement probe assembly. I'll continue to recommend that anyone considering a pH meter, please purchase a meter that has a cabled probe with a standard BNC style connector. That is the best way to assure that you can get standard replacement pH probes for the best market price and not beholden to the manufacturer for their proprietary replacement probe. More than likely, you will get a higher quality probe at a better price when choosing the industry-standard BNC-style probes.

PS: the 101 and 102 meters use the BNC probes. 
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