Author Topic: developing trust relationship w/new pH meter  (Read 1759 times)

Offline Susan38

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developing trust relationship w/new pH meter
« on: August 09, 2019, 08:14:56 PM »
I finally purchased and am using a pH meter!  What most convinced me to get one is Ms. Caldwell's video on her website https://gianacliscaldwell.com/2017/01/21/ph-and-acid-in-cheesemaking/

Then I read this forum board, hemmed and hawed over which one to get, read the forum board again, etc. etc. and finally settled on the Extech Exstik 110.

I started playing around with it and first off noticed the temperature sensor was very slow, sometimes not coming to temperature at all (while comparing to dairy thermometer which is frequently calibrated to a lab quality mercury thermometer).  And some of the pH measurements seemed a little hooey.  I remember a forum post where someone else had a similar problem, contacted Extech and eventually had it replaced with a new one...so I thought that was the next step for me.  But I kept working with it and now I think it is OK.  I think the problems were due to me not cleaning it often enough, and, more importantly, swirling the gadget around in the liquid that is being measured!  Prior to this I was gingerly putting the probe into the liquid and leaving it in place, much as you might a thermometer.  Swirling it around really seems to kick the sensors into gear for some reason.  The thermometer is still slower than the pH reading, but it does now correspond to my other thermometers.  And the pH readings are very consistent now.  So I think the meter is OK?

I did an official test with a quick mozz recipe.  It was a new experience for me, to set up not just  the cheese making equipment, but in addition, the pH "support system"   :)  What seems to work best is having the 4 and 7 buffer solutions, rinsing solution/distilled water, warm soapy water in small containers near the sink where I can also briefly rinse the electrode under tap water during the cleanings.  First calibrating at 7, rinse, calibrate at 4, rinse...take reading at 7 to make sure it is correct, rinse, take reading at 4, rinse, take reading of milk, wash, rinse, etc. Oh and I read somewhere to keep the electrode wet during the cheese make when not in use, so I was keeping it in the rinsing solution/distilled water in between readings.  Anyway, I was taking so many measurements this first time around I ended up recalibrating it several times.  But I was getting very consistent results so I think I'm getting accurate readings.

It is a new routine to add to the cheese making one! As someone who wrote into this forum previously expressed, you can get so caught up in the pH measurement routine that you can completely miss the timing on the cheese recipe, LOL, especially when doing something so fast like a quick mozzarella.  Hopefully with more use it will quickly become habit.

Anyway, if anyone reading this with experience with pH meters, thinks something may be off with my pH meter based on what I've written here, I'd appreciate any input.  And, for more info, I will be posting the pH results of this mozz make soon in the Pasta Filata board.

I am really excited about having a new way to evaluate my cheese makes, and really hoping it will lead to improvement of my future cheeses!

Offline scasnerkay

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Re: developing trust relationship w/new pH meter
« Reply #1 on: August 10, 2019, 04:26:28 AM »
This is from a communication I had with Extech when I was worried about my electrode funtion.

Reset the meter

Remove the battery cartridge from the unit.
Hold down toe On/Off button for 10 seconds
Re-insert the battery cartridge.

Rinse the probe with distilled water and wipe it off.

Place it into a sample of PH7.
Leave it in the PH7 for about 20 to 30 seconds and THEN press the CAL button.
When the PH7 cal has completed, remove the probe.

Rinse the probe with distilled water and wipe it off.

Place it into a sample of PH4.
Leave it in the PH4 for about 20 to 30 seconds and THEN press the CAL button.
When the PH4 cal has completed, remove the probe.

Turn off the meter.

Turn it back on.

Do not press any buttons - Measure one of the Calibration buffers to see how accurate your meter is reading.

 
Susan

Offline awakephd

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Re: developing trust relationship w/new pH meter
« Reply #2 on: August 10, 2019, 08:37:26 PM »
I had a similar learning curve with the Extech meter. The key for me has been to clean the tip thoroughly with soapy water (regular tap water + dish soap), rinse thoroughly, and dry with a paper towel. When taking a reading in whey, this is usually sufficient to get consistent readings, but when pressing into curd, I find I need to take several readings, since the first one or two may be off. Yes, the temperature reading is very slow and not particularly accurate - if reading whey, I generally hold the meter in the whey for 20 - 30 seconds to let the temperature stabilize before turning it on. But even then, the temperature correction is more approximate than exact.
-- Andy

Offline Susan38

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Re: developing trust relationship w/new pH meter
« Reply #3 on: August 10, 2019, 11:45:44 PM »
Susan--Thanks so much for the info!  You saved me a phone call to Extech with the associated time involved.  One would think this info should be included in the *very limited information* user guide that comes with the meter, eh?

Andy--Thanks for your insights, very helpful!  Especially the curd measurement process, I do not feel like I'm getting good reading on that yet.  Will try doing what you do in the future and see how that works.

And upon reading both posts, and reviewing Caldwell's pH video yet again, the one thing I have not been doing is wiping/drying the electrode after rinsing.  Caldwell says to use some kind of fancy lint-free cloth, but will a paper towel do?  I've been afraid to touch the electrode, LOL!  Anyway, I will be doing another quick mozz make tomorrow including more pH measurement and hope to keep dialing in the pH process, so to speak.

Thanks again, *really* appreciate the input/feedback.

Offline awakephd

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Re: developing trust relationship w/new pH meter
« Reply #4 on: August 11, 2019, 02:10:14 PM »
All I've ever used is a paper towel. Don't know if that is correct or not, but it has seemed to work for several years now!
-- Andy

Offline scasnerkay

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Re: developing trust relationship w/new pH meter
« Reply #5 on: August 13, 2019, 04:39:37 AM »
Yep, paper towel here too. I just try to blot rather than rub the glass tip.
Susan

Offline Susan38

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Re: developing trust relationship w/new pH meter
« Reply #6 on: August 15, 2019, 11:12:53 PM »
Thanks to you both!  Paper towel it is. (This is yet another thing they should add to the user manual, LOL.)

Offline awakephd

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Re: developing trust relationship w/new pH meter
« Reply #7 on: August 16, 2019, 05:04:50 PM »
You got a user manual??

J/K - I remember getting something or other. But it was pretty minimal, as I recall ...
-- Andy