Author Topic: pH Meters - Important Info!  (Read 4683 times)

Offline Cartierusm

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pH Meters - Important Info!
« on: February 16, 2009, 03:08:35 PM »
Ok, I've said this a few times in other posts but thought I would start a new thread to make sure people understand.

YOU HAVE TO TAKE A SAMPLE. You can't put the meter directly in the milk. I just got off the phone with Hanna Instruments for the second time and this guy knew what he was talking about. The electrode PH meters use leak electrolites into the sample. He said it's a very minute amount but shouldn't be used in the actual batch. You have to take a sample out, test it and then throw the sample away.

Just for a little more info, although I have a really expensive PH meter it doesn't go down to .01 decimal places, so I was going to get the one Wayne and Dave have, but the guy at Hanna said it doesn't have temperature correct. This means if the sample is anything other than 69.8 the PH will be off a little. Here is the temperature correction chart.

If your sample is 86F subtract .01, so if it reads 7.01 on the meter it is really 7.00.
86 = -.01
95 = -.02
104 = -.03
113 = -.03
122 = -.03
131 = -.03

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Offline Likesspace

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Re: pH Meters - Important Info!
« Reply #1 on: February 16, 2009, 08:15:54 PM »
Carter, this is great information but also not GOOD information for me!
For one, I was dipping my meter into the milk and curd the entire way. Do you think this could have contaminated my cheese?
Also, when you say "If the sample is anything other than 69.8" are you talking about the fresh milk reading?
Now you've given me something to worry about.
I really appreciate the information (and especially the temperature correction chart) but this concerns me.

Dave

Offline H.A.M.

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Re: pH Meters - Important Info!
« Reply #2 on: February 16, 2009, 08:20:31 PM »
I think that would mean if the sample is anything other than 69.8 degrees F.... That particular meter is calibrated for 69.8 degrees and doesn't automatically adjust for temperature.

Offline Likesspace

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Re: pH Meters - Important Info!
« Reply #3 on: February 16, 2009, 08:29:13 PM »
Okay, that makes sense. Sheesh I can be dense at times.
Tanks H.A.M.
I appreciate it.
Sounds as if it will be a bit of a pain using my meter in the future but I guess not overly so.
To me the temperature correction will not be nearly as big of a pain as having to remove a sample before each test.


Dave

Offline Cartierusm

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Re: pH Meters - Important Info!
« Reply #4 on: February 16, 2009, 09:36:12 PM »
Dave the guy at Hanna said it's a minute amount and should be avoided but probably won't hurt. He said definately don't do it in the future, always take a sample. Ham is right you're meter is calibrated for room temp. You should always take the reference sample when the milk has come up to temp 86F or so, because sometimes mine changed without adding starter. Starts out at 6.9 and then goes to 6.7 before adding starter.
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Offline chilipepper

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Re: pH Meters - Important Info!
« Reply #5 on: February 17, 2009, 05:30:09 PM »
I ordered one of these pH electrodes last week and they insist it will be fine for direct contact with both the raw milk and the cheese at all phases of production.  The really nice thing about it is that it is a flat surface electrode and will not need to necessarily be submerged to take a reading.  The other bonus is that it is also not made of glass for the risk of breaking and ruining a batch of cheese.

Quote
Hello Ryan,
The 601100 electrode should not leak electrolytes into your sample. You can place the electrode in your vat, just don’t place more than the white shaft in the liquid, and be sure to wipe the electrode before and after measurements.

Thanks,

Best Regards
Jamie Cohen
EXTECH Technical Support


Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #6 on: February 17, 2009, 05:33:21 PM »
what unit does it connect to?
Wayne A. Harris - in vino veritas

Offline Cartierusm

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Re: pH Meters - Important Info!
« Reply #7 on: February 17, 2009, 05:54:54 PM »
hee hee you said unit.

Wayne I think it is a universal BNC and will work with any hand held such as http://morebeer.com/view_product/18715//Milwaukee_pH_Meter_w_ATC

But wayne if you're going to follow in my footsteps and use TA then you have to take a sample anyway. If I only had to do PH then maybe I'd consider it.

Incidently I figured out a way to measure down to 20th of 1 ml, I use an eyedropper and measured it's water drops and I get 20 for 1 ml. So I can get real accurate.
« Last Edit: February 17, 2009, 06:09:59 PM by Cartierusm »
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Offline chilipepper

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Re: pH Meters - Important Info!
« Reply #8 on: February 17, 2009, 06:15:01 PM »
I actually scored one of these:



Heavy Duty pH/Temp Kit

Which is really cool because along with my score it has the software that will log both temp and pH to an Access database.  Plus it has cool little on screen gauges and graphs, etc. The electrode was not included, hence the reason I ordered the one above.  Should be pretty cool and stay tuned for graphs of pH over time included with my cheesemaking posts! :)

Offline Cartierusm

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Re: pH Meters - Important Info!
« Reply #9 on: February 17, 2009, 07:30:09 PM »
Dammm we've created a monster. Now all you need chili is an automatic titration station for measureing Titratable Acids from Hanna.

Wayne, uhhh, I hate to tell you this but Chili beat you to the punch for that idea we were talking about the other day. He's in ND maybe you can borough it... :D
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Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #10 on: February 17, 2009, 07:33:16 PM »

Its not the size of the probe that counts, its how you use it.

;)

Wayne A. Harris - in vino veritas

Offline Cartierusm

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Re: pH Meters - Important Info!
« Reply #11 on: February 17, 2009, 07:35:51 PM »
Well Wayne kind of went there, and I probably shouldn't so I won't I'll be good.
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Offline LadyLiberty

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Re: pH Meters - Important Info!
« Reply #12 on: February 18, 2009, 03:11:16 AM »
I will resist as well.

But you know, when I was reading this thread, I realized: We are a bunch of true nerds!

Offline Cartierusm

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Re: pH Meters - Important Info!
« Reply #13 on: February 18, 2009, 04:43:34 PM »
Speak for yourself Oh Hyperborean Wanderer.
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Offline Wayne Harris

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Re: pH Meters - Important Info!
« Reply #14 on: March 04, 2009, 01:14:46 PM »
Well, my little Hanna pH meter just crapped out. 

So, this batch (yet unposted) will yeild zero pH data. 

Damn.

Thoughts?  I am really ready to get a NICE one.  (well, lets not go too crazy), but I am open to sugestions.

Wayne A. Harris - in vino veritas