Author Topic: pH Meter, Help Needed  (Read 1264 times)

Offline rolsen99

  • Mature Cheese
  • ****
  • Location: Detroit Area, MI
  • Posts: 100
  • Cheeses: 3
  • Default personal text
pH Meter, Help Needed
« on: March 09, 2013, 07:02:23 PM »
So I was all excited today, after so many OK cheeses and a couple failures, I invested in a Extech pH110.  Decided to make a 4 gallon Stilton with my new toy.  Out of the box, I soaked it for 10 minutes per instructions in 4.0 solution.  I then did a 2 point calibration, 7 and 4.  After doing the 7, the meter took a while to get down to 4, but then calibrated.  I heated milk to 86 degrees, took a pH measurement, and it was at 6.6.  Perfect right?  After about 40 minutes, using bulk FD culture, I measured pH, and it is at 6.77???  How can this be?  Over the next hour and a half, the pH readings bounced around from 6.56 to 6.85.  I did multiple calibrations with 7.0 solution during the process trying to get something constant.  To no avail.  My other,  cheap meter, read 6.5 after about 2.5 hours, so I decided to rennet.

Anyway, the meter seems to react well (and fast) to water and the solutions, but doesn't seem to do well with the milk.  It is all over the place.  It is not consistent at all.....not even close.

Does anyone have any tips for me?  I am extremely frustrated as I have a feeling I have another fail.  Also, what methods to you use to test pH?  Do you just stick the meter in the pot?  Or do you pull some milk.  Also, do you store the meter in solution during make?  Any tips are appreciated.


Guests, join the CheeseForum.org community to remove this ad.


Offline tnbquilt

  • Mature Cheese
  • ****
  • Location: McDonough GA
  • Posts: 323
  • Cheeses: 13
Re: pH Meter, Help Needed
« Reply #1 on: March 09, 2013, 07:46:49 PM »
I just got one of these myself. When I started using it, I thought the same thing for awhile. I would write down the ph level, and next time it would be higher. I finally realized that I wasn't waiting long enough. I started putting the samples of the whey in the little cup and I would just set it over to the side and leave the room for a minute and come back and the numbers would be more what I expected to see. I'm thinking about 3 minutes.
Tammy

Offline rolsen99

  • Mature Cheese
  • ****
  • Location: Detroit Area, MI
  • Posts: 100
  • Cheeses: 3
  • Default personal text
Re: pH Meter, Help Needed
« Reply #2 on: March 09, 2013, 08:29:24 PM »
Thanks for the reply.  I am starting to wonder now if my bulk culture is no good.  I am still sitting at 6.55.  Think I am going to dump it :(

curd nerd

  • Guest
Re: pH Meter, Help Needed
« Reply #3 on: March 09, 2013, 09:01:38 PM »
rinse bulb in cool water between buffer solutions ,,,,,,change this rinsing water very frequently OR under a cold/cool

running tap,and YES you must soak bulb in clean water when not in use

these instruments usually have a built in temperature compensator so give this time to adjust

please read the instructions again as most of us miss something vital and like the old RAM and the young RAM on top of

the hill discussing the EWES in the paddock below,,,be patient ,,,,,,,,[ with pH metres of course]

many regards and good luck ,,,BRIAN


Offline scasnerkay

  • Mature Cheese
  • ****
  • Location: Sunnyvale, California
  • Posts: 376
  • Cheeses: 61
  • Default personal text
Re: pH Meter, Help Needed
« Reply #4 on: March 10, 2013, 11:27:31 AM »
My meter is a Hanna product. I was ready to throw it away due to variations in readings. But I think the problem was user error.  When I looked at the tip of the probe, I could see some film left on it from milk. I cleaned the probe with soaking the probe tip (still in the meter) in warm soapy water, rinsed in clean water, then for 30 minutes in the cleaning solution. I rinsed it well, then I did the 2 point calibration in the 7.0 and 4.0 solutions, rinsing under running water in between. After it was calibrated, I left it sitting in the 7.0 solution for about 30 mins before using. I rinsed the probe in running water, then I checked the milk by taking a small sample in a small bowl. It measured 6.7. Then I rinsed the probe well under running water, then let the probe rest on it's tip in the 7.0 solution before it's next use. Again, when measuring the whey pH I take a small sample out of the pot, rinse after checking, and back into the 7.0. Following this procedure, I think the readings are fairly accurate. I do recheck the probe reading in the 7.0 or the 4.0 solutions during the make to make sure I am on target. I know the probe tip will need replacing at some point, but am giving it TLC and patiently caring for it in the meantime.
Susan


Guests, join the CheeseForum.org community to remove this ad.


Offline bbracken677

  • Old Cheese
  • *****
  • Location: Dallas, Tx
  • Posts: 1,166
  • Cheeses: 16
  • I love me some cheese!
Re: pH Meter, Help Needed
« Reply #5 on: March 10, 2013, 11:52:06 AM »
One thing I have found to be helpful, since my meter sits in a cup of distilled water between uses (during the make)...I place the tip in the milk and give it little swooshes around to make sure it is the milk that is in contact with the important part and not some bubble of water still clinging...once the swishing is done it usually settles down to an expected measurement.

I too have the Extech 110.

Offline Shazah

  • Medium Cheese
  • ***
  • Location: Auckland, New Zealand
  • Posts: 96
  • Cheeses: 5
Re: pH Meter, Help Needed
« Reply #6 on: March 10, 2013, 01:45:06 PM »
Thanks all for the tips here.

I've also had problems similar to rolsen99 so am happy to try the remedies suggested here.

I wasn't enjoying my cheesemaking as much with the Ph meter not recording the numbers I was expecting and was just about to give up on it and go back to not using one.  I'll try these suggestions for an improved performance, hopefully. ^-^

Cheers
Sharon
You have to be a romantic to invest yourself, your money, and your time in cheese.
― Anthony Bourdain

Offline rolsen99

  • Mature Cheese
  • ****
  • Location: Detroit Area, MI
  • Posts: 100
  • Cheeses: 3
  • Default personal text
Re: pH Meter, Help Needed
« Reply #7 on: March 10, 2013, 05:31:28 PM »
Thanks for all the tips.  On my next make, I will follow them.

I think that part of my issue was due to the lack of acidification of my bulk culture.  I ended up dumping the entire make, because I couldn't get the pH below 6.55.

Any thoughts here?  I followed Sailors write up to create the mother culture, and is the first time I tried using it.  I thawed it in warm water.  The only thing I can think is that my water was too warm and killed the culture?  So confused......

Offline Sailor Con Queso

  • Old Cheese
  • *****
  • Location: Kentucky
  • Posts: 2,539
  • Cheeses: 127
    • Boone Creek Creamery
Re: pH Meter, Help Needed
« Reply #8 on: March 10, 2013, 09:19:43 PM »
Don't thaw out the cubes in water. Yes you can kill the bacteria if the water is too hot, but you also risk contaminating the culture. Just toss them into your milk.
A moldy Stilton is a thing of beauty. Yes, you eat the rind. - Ed
www.boonecreekcreamery.com

Offline rolsen99

  • Mature Cheese
  • ****
  • Location: Detroit Area, MI
  • Posts: 100
  • Cheeses: 3
  • Default personal text
Re: pH Meter, Help Needed
« Reply #9 on: March 13, 2013, 07:15:27 PM »
OK, I will try just adding them directly next time.  Gun shy to even try another after all these disasters.


Guests, join the CheeseForum.org community to remove this ad.


Offline barnaclebob

  • New Cheese
  • *
  • Location: The Pacific Northwest
  • Posts: 1
  • Cheeses: 0
  • Default personal text
Re: pH Meter, Help Needed
« Reply #10 on: April 16, 2013, 01:20:54 PM »
I have the Extech 110 that I have used for salami (just bought my cheese supplies).  Check the reference junction on the electrode to make sure its not cracked.  If you unscrew it and the threaded part is stuck in the hole then you have problems...

I had Extech send me 4 (yes 4) of the electrodes before i got one that didn't have a broken reference junction that left the threaded part stuck in the hole.  But Extech did all of the replacements no questions asked and didn't make me mail back the defective units.  I figured out that you can drill out the broken reference junctions and replace them with the spares and still get good readings.

Offline Boofer

  • Old Cheese
  • *****
  • Location: Parkland, Washington
  • Posts: 4,226
  • Cheeses: 203
  • Contemplating cheese
Re: pH Meter, Help Needed
« Reply #11 on: April 16, 2013, 06:36:18 PM »
Don't thaw out the cubes in water. Yes you can kill the bacteria if the water is too hot, but you also risk contaminating the culture. Just toss them into your milk.
I'm coming to this thread a little late...sorry. :(

I started out putting the frozen cubes into the milk and heating both up to ripening temp. I wasn't pleased that the cubes could be persistent and not thaw quickly enough. Then I moved to thawing the vacuum bag of frozen cubes to a bowl of tepid water. There they thaw quickly and safely without prematurely "cooking" the cultures. They go into the bowl to thaw about the same time as I start heating the milk. Both meet in the middle and we're all happy.  ;)

-Boofer-
Let's ferment something!
Bread, beer, wine, cheese...it's all good.