Author Topic: How to use a pH meter  (Read 7941 times)

Offline Pinski

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Re: How to use a pH meter
« Reply #15 on: March 23, 2012, 08:28:45 AM »
I bought a pH meter last night and was reading some past posts to prepare to use it next week, great discussion here. So I think the biggest questions I have are... At what points in the mash process should samples be taken and tested and if necessary, adjustments made?  At what point do you stop sampling/adjusting? Pre-boil? Pre-pitch?
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Offline hokerer

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Re: How to use a pH meter
« Reply #16 on: March 23, 2012, 08:33:09 AM »
I bought a pH meter last night and was reading some past posts to prepare to use it next week, great discussion here. So I think the biggest questions I have are... At what points in the mash process should samples be taken and tested and if necessary, adjustments made?  At what point do you stop sampling/adjusting? Pre-boil? Pre-pitch?

The only time I really check/worry about pH is at the beginning of the mash.  Mash in and give it a little time to settle and then check the pH.  Add whatever that reading tells you that you need to add, give it a little more time and check the pH again to see that your additions did what you expected.
Joe

Offline brewmichigan

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Re: How to use a pH meter
« Reply #17 on: March 23, 2012, 10:06:43 AM »
Martin I hope you save all this info in a word doc or something so you just cut and paste when someone else asks a similar question in the future. I'd hate to write all that down all the time. Very good info indeed!
Mike --- Flint, Michigan

Offline redzim

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Re: How to use a pH meter
« Reply #18 on: March 24, 2012, 05:20:25 AM »
Can anyone recommend to me a decent pH meter that they use?  I have been using a Milwaukee MW102 for a year and sadly it does not seem consistent. Drifts all over the place even in buffers.  I just sent it in to the factory, they replaced the temp probe and and returned it to me but it still does wierd stuff like this: you calibrate it in 7.01 buffer, then in 4.10 buffer, and if you leave it in the 4.01 buffer, within 1 minute it is reading 3.85 or 3.90....  or if, after calibration, you measure a sample of mash, vinegar or windex, then rinse the probe and put it back into the 4.01 buffer, it can read anywhere from 3.60  to 4.20... but certainly not right around 4.01....

Anyone have a better manufacturer to recommend to me? I'm getting a little fed up with Milwaukee... I'm on the phone with their techs about every brew session lately.... or can anyone tell if I am doing something wrong?

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Offline euge

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Re: How to use a pH meter
« Reply #19 on: March 24, 2012, 10:21:18 AM »
Hanna instruments are available everywhere and are reliable: http://www.hannainst.com/usa/subcat.cfm?id=002
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Offline redzim

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Re: How to use a pH meter
« Reply #20 on: March 24, 2012, 12:01:11 PM »
Hanna instruments are available everywhere and are reliable: http://www.hannainst.com/usa/subcat.cfm?id=002

what model do you use?

Offline euge

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Re: How to use a pH meter
« Reply #21 on: March 24, 2012, 12:10:27 PM »
Hanna instruments are available everywhere and are reliable: http://www.hannainst.com/usa/subcat.cfm?id=002

what model do you use?

Hanna Champ HI98106 for around $30

Manual calibration but that is a plus! And extremely easy to do. I'll only go with manual calibrating meters from now on.
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

Offline Pinski

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Re: How to use a pH meter
« Reply #22 on: March 24, 2012, 01:19:08 PM »
My model is the 98018. I'll take it for a spin on three batches this week and report back.
Steve Carper
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Offline narvin

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Re: How to use a pH meter
« Reply #23 on: March 24, 2012, 07:51:01 PM »
Did they try replacing the probe?  I have the MW 102 and haven't really had any problems with it.  When you see the hour glass go away, you should be able to take a reading.  It may drift a little after that, but not by as much as you're seeing.  You should be moving the probe around slowly as you take the reading;  otherwise, diffusion from the probe can affect the sample directly in contact with it.

I pulled mine out of the storage solution after a month and the 4.01 solution reading was dead on, and the 7.01 read around 6.98.
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Offline ccfoo242

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Re: How to use a pH meter
« Reply #24 on: March 26, 2012, 11:05:08 AM »
This one looks sweet: http://www.amazon.com/Extech-PH100-ExStik-Waterproof-Meter/dp/B00023RYQ8/ref=sr_1_1?ie=UTF8&qid=1332784821&sr=8-1



  • resolution of 0.01 pH and an accuracy +/-0.01 pH
  • Memory recall of up to 15 sequentially labeled readings allows you to track how readings have changed over time.

$90....I guess I could skip lunch for a few weeks to pay for it!  ;D

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Offline redzim

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Re: How to use a pH meter
« Reply #25 on: March 29, 2012, 11:53:51 AM »
Did they try replacing the probe?  I have the MW 102 and haven't really had any problems with it.  When you see the hour glass go away, you should be able to take a reading.  It may drift a little after that, but not by as much as you're seeing.  You should be moving the probe around slowly as you take the reading;  otherwise, diffusion from the probe can affect the sample directly in contact with it.

I pulled mine out of the storage solution after a month and the 4.01 solution reading was dead on, and the 7.01 read around 6.98.

I got to Milwaukee tech support again today and they agree that my meter seems flaky. They are going to replace it free of charge so we'll see if that helps.


Offline nateo

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Re: How to use a pH meter
« Reply #26 on: March 29, 2012, 12:28:35 PM »
I've been getting some odd readings on my Hanna HI 98107 (the 2-point calibration one). I read the label on my buffer solutions, and it said not to pour the used solution back into the bottle. D'oh! I've been doing that for the past year or so.

I've ordered some new buffers, but I wonder which direction the old solution would push the pH, up or down? 

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Offline mabrungard

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Re: How to use a pH meter
« Reply #27 on: March 29, 2012, 12:45:10 PM »

I got to Milwaukee tech support again today and they agree that my meter seems flaky. They are going to replace it free of charge so we'll see if that helps.

I've had the Hanna meters for years and they are alright.  I recently moved to Milwaukee meters and am pleased.  I use the MW-101 and it works very well.  Hopefully this replacement will solve your problems.
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Offline punatic

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Re: How to use a pH meter
« Reply #28 on: March 29, 2012, 05:56:46 PM »
I've been getting some odd readings on my Hanna HI 98107 (the 2-point calibration one). I read the label on my buffer solutions, and it said not to pour the used solution back into the bottle. D'oh! I've been doing that for the past year or so.

I've ordered some new buffers, but I wonder which direction the old solution would push the pH, up or down?

As a rule in bench chemistry, one should never return excess chemicals to the original container once they have been removed from the original container.  This is to avoid contaminating the entire container.

That said; they are called buffers because they are made specifically to resist pH change.  I wouldn't be too overly concerned with the buffers not maintaining their stated pH value.  Unless you contaminated the portion that you removed and returned, e.g. with rinse water from rinsing the pH probe off.
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Offline nateo

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Re: How to use a pH meter
« Reply #29 on: March 30, 2012, 07:48:34 AM »
Unless you contaminated the portion that you removed and returned, e.g. with rinse water from rinsing the pH probe off.

That's what I'm afraid happened. My tap water is really alkaline, so maybe if half a ml of rinse water contaminated it each time I calibrated it, after a long time that could skew the samples. When my new buffers show up I'll compare the results.
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