Author Topic: Inconsistent pH readings...  (Read 4023 times)

Online ibru

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Re: Inconsistent pH readings...
« Reply #15 on: March 01, 2012, 08:43:11 AM »
Keith- Which ph meter do you have? Wife is asking for birthday suggestions, just what to help her out...

Bruce

Offline bluesman

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Re: Inconsistent pH readings...
« Reply #16 on: March 01, 2012, 10:35:59 AM »
I think temperature and pH accuracy are equally important for different reasons. They can both create problems with your beer if they are far enough out of range. Calibration of both measuring devices is important for that reason. NIST traceable standards are the best way to go when calibrating your meter or thermometer. I use pH buffer solutions to calibrate my meter.
Ron Price

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Re: Inconsistent pH readings...
« Reply #17 on: March 01, 2012, 12:35:42 PM »
Keith- Which ph meter do you have? Wife is asking for birthday suggestions, just what to help her out...

Bruce

Milwaukee SM101
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Offline redzim

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Re: Inconsistent pH readings...
« Reply #18 on: March 03, 2012, 07:44:02 AM »
this thread is interesting, I was going to start a new thread with some q's about my Milwaukee pH meter but I'll hijack 'em into this one....

I have the MW102 http://www.amazon.com/Milwaukee-MW102-14-00-%C2%B5P-Based-Meter/dp/B001DTNDME/ref=sr_1_1?ie=UTF8&qid=1330785089&sr=8-1 which is just the MW101 that others have, with ATC (I believe this is an update of the SM101 and SM102 line which major has?)

anyways this is what happens which i check mash pH... I'm just copying in notes from an Altbier batch about 2 wks ago: "calibrated meter to 7.01 and then 4.01 buffers. read pH of 5.46 @ 24.7*C.  then put meter in 4.01 buffer. it reads 3.79.  now checked 7.01 buffer, it reads 7.03. now back into mash sample, it reads 5.63 at 21.6*C."  (my brew room is about 55F this time of year so the sample keeps cooling as I'm checking it)

and from 1 month ago, a Boh Pils: "calibrated meter to 7.01 and then 4.01 buffers. read pH of 5.27 @ 28.9*C.  then put meter in 4.01 buffer. it reads 3.73.  now checked 7.01 buffer, it reads 6.89. now back into mash sample, it reads 5.34 at 20.7*C." 

now maybe this is all within the margin of error for this meter and probe, and it's all "good enough" and I should RDWHAHB etc etc... although I am one who likes to know that what I am getting is really what's there... or what are you other guys with Milwaukee meters seeing?  I use the Hanna storage solution, and the Hanna 4.01 and 7.01 buffer packs from Amazon (I once called Milwaukee and they said it is OK to use Hanna products on their meters)

finally, if mash pH does change during the mash, when do you check it??? I asked this a bout a year ago on this forum, and it seems like most people take it about 5 or 10 minutes after dough-in? of course it takes 10-15 minutes for the sample to cool (I try to consistently read pH around 20-25*C [68-77*F] even though I have ATC).  what are you guys doing about this?

-red

Offline bluesman

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Re: Inconsistent pH readings...
« Reply #19 on: March 03, 2012, 07:56:53 AM »
this thread is interesting, I was going to start a new thread with some q's about my Milwaukee pH meter but I'll hijack 'em into this one....

I have the MW102 http://www.amazon.com/Milwaukee-MW102-14-00-%C2%B5P-Based-Meter/dp/B001DTNDME/ref=sr_1_1?ie=UTF8&qid=1330785089&sr=8-1 which is just the MW101 that others have, with ATC (I believe this is an update of the SM101 and SM102 line which major has?)

anyways this is what happens which i check mash pH... I'm just copying in notes from an Altbier batch about 2 wks ago: "calibrated meter to 7.01 and then 4.01 buffers. read pH of 5.46 @ 24.7*C.  then put meter in 4.01 buffer. it reads 3.79.  now checked 7.01 buffer, it reads 7.03. now back into mash sample, it reads 5.63 at 21.6*C."  (my brew room is about 55F this time of year so the sample keeps cooling as I'm checking it)

and from 1 month ago, a Boh Pils: "calibrated meter to 7.01 and then 4.01 buffers. read pH of 5.27 @ 28.9*C.  then put meter in 4.01 buffer. it reads 3.73.  now checked 7.01 buffer, it reads 6.89. now back into mash sample, it reads 5.34 at 20.7*C." 

now maybe this is all within the margin of error for this meter and probe, and it's all "good enough" and I should RDWHAHB etc etc... although I am one who likes to know that what I am getting is really what's there... or what are you other guys with Milwaukee meters seeing?  I use the Hanna storage solution, and the Hanna 4.01 and 7.01 buffer packs from Amazon (I once called Milwaukee and they said it is OK to use Hanna products on their meters)

finally, if mash pH does change during the mash, when do you check it??? I asked this a bout a year ago on this forum, and it seems like most people take it about 5 or 10 minutes after dough-in? of course it takes 10-15 minutes for the sample to cool (I try to consistently read pH around 20-25*C [68-77*F] even though I have ATC).  what are you guys doing about this?

-red

How old is your pH meter probe?

They last about 18-24mos if kept clean and wet in the proper storage solution.

Anyway, I check the mash pH about 10 min into the mash and the sparge after stirring for 2 min. I always calirate with 4.01 and 7.0 prior to the mash and the sparge. I typically get readings within +/-.02 upon calibration, so you either have a failing probe or stray voltage in your system. I recommend contacting Milwaukee and talking to their tech support folks.

One other thing to consider is your sampling temp. I always chill the mash sample down to RT prior to taking a reading.
Ron Price

Offline redzim

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Re: Inconsistent pH readings...
« Reply #20 on: March 03, 2012, 08:44:33 AM »
How old is your pH meter probe?

They last about 18-24mos if kept clean and wet in the proper storage solution.

Anyway, I check the mash pH about 10 min into the mash and the sparge after stirring for 2 min. I always calirate with 4.01 and 7.0 prior to the mash and the sparge. I typically get readings within +/-.02 upon calibration, so you either have a failing probe or stray voltage in your system. I recommend contacting Milwaukee and talking to their tech support folks.

One other thing to consider is your sampling temp. I always chill the mash sample down to RT prior to taking a reading.

Meter and probe are less than 1yr old... has been stored in proper storage solution for the duration... as I said, I also cool samples to around 65-80F before taking a reading....     so I guess a call to Milwaukee is next...

-red