Frequency of pH meter calibration

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guypettigrew
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Frequency of pH meter calibration

Post by guypettigrew » Thu Nov 22, 2018 9:12 pm

How often do you calibrate your pH meter? Mine's a Voltcraft pH100-ATC.

It needs calibrating every brew. Not really a problem, but I'd have thought a meter of this calibre would hold its calibration much longer.

Guy

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LeeH
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Re: Frequency of pH meter calibration

Post by LeeH » Thu Nov 22, 2018 10:17 pm

Every brew day.


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Kev888
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Re: Frequency of pH meter calibration

Post by Kev888 » Thu Nov 22, 2018 10:37 pm

Every brew day, here too; it usually isn't much out, although that can increase with age of the probe. I guess in many homebrewer's usage, quite a bit of time (and possibly temperature etc) passes between brews.

It can also be worth making sure unused calibration solutions are employed each time. If you re-use the same fluid, or return what you have used to the main bottle, the two pHs can gradually become contaminated with each other as the probe is moved between the two (it is hard to dry it off completely). This might cause an apparent creep in addition to any real one.
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Jocky
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Re: Frequency of pH meter calibration

Post by Jocky » Thu Nov 22, 2018 11:22 pm

If I'm going to use it, I calibrate it. I have the same model and it barely moves out of calibration, even over months.
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Eric
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Re: Frequency of pH meter calibration

Post by Eric » Thu Nov 22, 2018 11:40 pm

Jocky wrote:
Thu Nov 22, 2018 11:22 pm
If I'm going to use it, I calibrate it. I have the same model and it barely moves out of calibration, even over months.
Yes, mine hardly varies with time. It is important to rinse with running deionised water between readings and during calibration, with any surplus liquor wicked away. The probe should also be kept in suitable storage solution.

Does the BNC plug and socket fit together firmly?
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Aleman
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Re: Frequency of pH meter calibration

Post by Aleman » Fri Nov 23, 2018 10:27 am

<QualitativeLabMode>

Every single time you take a reading!

</QualitativeLabMode>

In all reality every brew day, it's not a big deal, must admit that my Oakton doesn't move all that much between calibrations, and I am only brewing a couple of times a year.

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Re: Frequency of pH meter calibration

Post by Robwalkeragain » Fri Nov 23, 2018 10:43 am

Suppose it depends how slack you're willing to be with your brewing processes, which probably negates the point of buying a pH meter...will it fall out far? Probably not. If you want accuracy, yep, every time!

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Re: Frequency of pH meter calibration

Post by guypettigrew » Fri Nov 23, 2018 11:54 am

Thanks all--seems like calibrating each brewday would be a good idea.

Eric--the BNC plug and socket are a nice tight fit. I use reverse osmosis water to rinse between readings and throw the buffer solutions away after use.

I calibrated it yesterday. I'll try it again in a week or so and see if it's slipped much.

Guy

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Re: Frequency of pH meter calibration

Post by Dave S » Sat Nov 24, 2018 12:11 pm

guypettigrew wrote:
Fri Nov 23, 2018 11:54 am
Thanks all--seems like calibrating each brewday would be a good idea.

Eric--the BNC plug and socket are a nice tight fit. I use reverse osmosis water to rinse between readings and throw the buffer solutions away after use.

I calibrated it yesterday. I'll try it again in a week or so and see if it's slipped much.

Guy
I too have a Voltcraft and I calibrate every brew day just before taking a reading. As others have said, it doesn't drift much between calibrations, but it does drift.
Best wishes

Dave

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