Jump to content

  • Quick Navigation
Photo
- - - - -

Can temperature affect pH reading?


  • You cannot start a new topic
  • Please log in to reply
18 replies to this topic

carine

    Grade - SIFSQN

  • IFSQN Senior
  • 338 posts
  • 22 thanks
5
Neutral

  • Earth
    Earth

Posted 02 June 2020 - 04:56 AM

Hi all, 

 

Lately our finished product which is ice pH reading lower than stipulated standards, lab operator was saying this is due to pH checking not done at room temperature? Wondering how true is it?   



zanorias

    Grade - PIFSQN

  • IFSQN Principal
  • 802 posts
  • 242 thanks
156
Excellent

  • Wales
    Wales
  • Gender:Male
  • Location:UK
  • Interests:Motorcycling, Food Safety, Science, Paddleboarding, Space

Posted 02 June 2020 - 05:22 AM

Hi Carine,

 

I hadn't heard of this being the case but a little Googling suggets your lab operative may be right:

 

https://www.preclabo...ph-test-strips/

https://www.westlab....ature-affect-ph



pHruit

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,867 posts
  • 737 thanks
447
Excellent

  • United Kingdom
    United Kingdom
  • Gender:Male
  • Interests:Composing/listening to classical music, electronics, mountain biking, science, sarcasm

Posted 02 June 2020 - 07:50 AM

Yes, it can definitely be affected by temperature - having more (or less) thermal energy in the system will potentially affect the concentration of H+ ions, and this is effectively what pH is measuring.

It's often overlooked, but to be useful a pH tolerance and method should really reference the temperature at which the measurement is made.



Thanked by 2 Members:

olenazh

    Grade - PIFSQN

  • IFSQN Principal
  • 838 posts
  • 251 thanks
240
Excellent

  • Canada
    Canada
  • Gender:Female
  • Location:Toronto
  • Interests:My job, church, reading, gym, horror movies

Posted 02 June 2020 - 12:35 PM

We had this issue: temperature fluctuated in cooled and room temp products. Here's the lab scientist's explanation:

pH is defined as being at room temperature.  Higher or lower temperatures vary the pH by a small percent either way.  See the chart attached.

    

Attached Files



olenazh

    Grade - PIFSQN

  • IFSQN Principal
  • 838 posts
  • 251 thanks
240
Excellent

  • Canada
    Canada
  • Gender:Female
  • Location:Toronto
  • Interests:My job, church, reading, gym, horror movies

Posted 02 June 2020 - 12:36 PM

We had this issue: temperature fluctuated in cooled and room temp products. Here's the lab scientist's explanation:

pH is defined as being at room temperature.  Higher or lower temperatures vary the pH by a small percent either way.  See the chart attached.

My apologies: not temperature fluctuated, the pH.



SQFconsultant

    SQFconsultant

  • IFSQN Fellow
  • 3,821 posts
  • 960 thanks
852
Excellent

  • United States
    United States
  • Gender:Male
  • Interests:American Patriot
    WWG1WGA
    Never give up, never give in - always win!
    Martha's Vineyard Island, Massachusetts

Posted 02 June 2020 - 01:43 PM

It's true, have been in more ice manufacturers than I can count and the testing method is what your lab person is saying.


Kind regards,
Glenn Oster
 
GOC BUSINESS GROUP | SQF System Development, Implementation & Certification Consultants
Internal Auditor Training - eConsultant - Pre & Post SQF-GAP Audits - Consultant Training
Visit us @ http://www.GlennOster.com  or call us @ 772.646.4115 US-EST 8am-4pm Anyday except Thursday
 
 

carine

    Grade - SIFSQN

  • IFSQN Senior
  • 338 posts
  • 22 thanks
5
Neutral

  • Earth
    Earth

Posted 02 June 2020 - 03:45 PM

It's true, have been in more ice manufacturers than I can count and the testing method is what your lab person is saying.

IN that case, what are the solution for this since u have many experience in ice manufacturing. This made me cracking my head, because our ingredient is pure water and doesn't add in anything into process till it form ice, so maintaining the pH abit difficult to us.  



Setanta

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,273 posts
  • 313 thanks
255
Excellent

  • United States
    United States
  • Gender:Female
  • Interests:Reading: historical fiction, fantasy, Sci-Fi
    Movies
    Gardening
    Birding

Posted 02 June 2020 - 04:19 PM

If you always take the pH reading at the same temperature, it should be pretty consistent


-Setanta         

 

 

 


FurFarmandFork

    Food Safety Consultant, Production Supervisor

  • IFSQN Fellow
  • 1,264 posts
  • 585 thanks
194
Excellent

  • United States
    United States
  • Gender:Male
  • Location:Oregon, USA

Posted 02 June 2020 - 05:56 PM

If you're using a probe, some of them compensate for temperature, it just takes a while for them to equalize.

 

https://support.hach...ph-measurement?


Austin Bouck
Owner/Consultant at Fur, Farm, and Fork.
Consulting for companies needing effective, lean food safety systems and solutions.

Subscribe to the blog at furfarmandfork.com for food safety research, insights, and analysis.

pHruit

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,867 posts
  • 737 thanks
447
Excellent

  • United Kingdom
    United Kingdom
  • Gender:Male
  • Interests:Composing/listening to classical music, electronics, mountain biking, science, sarcasm

Posted 03 June 2020 - 10:58 AM

IN that case, what are the solution for this since u have many experience in ice manufacturing. This made me cracking my head, because our ingredient is pure water and doesn't add in anything into process till it form ice, so maintaining the pH abit difficult to us.  

 

If you're having issues hitting your pH range then I'd start by looking at your historical data to assess what the actual range of your water source is. Whilst some potable sources are relatively consistent, some are inherently somewhat variable. If there is a large natural variation then it's possibly also worth considering what may cause this, as whilst natural variation is not a problem, you do need to be able to be sure that this is indeed natural and not some sort of other factor that could affect the potability of the supply. If you're using a mains/municipal supply then the authority from whom you source the water will almost certainly be able to provide summary data from their own monitoring, which will be a useful guide/starting point.

 

Does pH matter in the product? i.e. what is the consequence of it being out of spec? If it's just a guide to reflect the expected range of the raw material then you should be able to align the two based on the nature of that raw material.

Otherwise, making ice with a pH range that is different to the water from which it's made sounds very much like a situation that will create unnecessary challenges!



Ryan M.

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,261 posts
  • 456 thanks
258
Excellent

  • United States
    United States
  • Gender:Male
  • Location:Birmingham, AL
  • Interests:Reading, crosswords, passionate discussions, laughing at US politics.

Posted 03 June 2020 - 01:40 PM

Yes.  Is there anything in the ice by chance?  Or just water?  If you have other things, additives, flavors, etc you can get different pH readings due uneven distribution and the measurement only able to test the surface.

 

If it isn't an issue I'd melt the ice before testing.  It will give you a more repeatable and representative pH.  Make sure to use an probe with ATC compensation.



mcright

    Grade - Active

  • IFSQN Active
  • 4 posts
  • 3 thanks
1
Neutral

  • Spain
    Spain

Posted 03 June 2020 - 01:50 PM

I attended a Mettler-Toledo webinar about pH mesurament yesterday. pH depends on the temperature of your sample and they said that the pH must always be accompanied of the temperature at what you did the analyse. They also said that you don't "compensate", the device is giving you the pH at that particular temperature (I thought that the pHmeter compensates temperature, I was wrong). So the best thing to compere pH values of a product is to analyse always at the same temperature. 



carine

    Grade - SIFSQN

  • IFSQN Senior
  • 338 posts
  • 22 thanks
5
Neutral

  • Earth
    Earth

Posted 03 June 2020 - 03:09 PM

Dear pHruit, 

 

In our country raw water and ice shared same standard under the food act, in other words, pH for raw water n ice will be the same which is 6,5-8.5  . To me not a big deal if pH of the product out of spec, but  from local authorities view , our finished product is not comply to the law, and we have to take corrective action on this. 

If you're having issues hitting your pH range then I'd start by looking at your historical data to assess what the actual range of your water source is. Whilst some potable sources are relatively consistent, some are inherently somewhat variable. If there is a large natural variation then it's possibly also worth considering what may cause this, as whilst natural variation is not a problem, you do need to be able to be sure that this is indeed natural and not some sort of other factor that could affect the potability of the supply. If you're using a mains/municipal supply then the authority from whom you source the water will almost certainly be able to provide summary data from their own monitoring, which will be a useful guide/starting point.

 

Does pH matter in the product? i.e. what is the consequence of it being out of spec? If it's just a guide to reflect the expected range of the raw material then you should be able to align the two based on the nature of that raw material.

Otherwise, making ice with a pH range that is different to the water from which it's made sounds very much like a situation that will create unnecessary challenges!



carine

    Grade - SIFSQN

  • IFSQN Senior
  • 338 posts
  • 22 thanks
5
Neutral

  • Earth
    Earth

Posted 03 June 2020 - 03:09 PM

Thanks for the info 

I attended a Mettler-Toledo webinar about pH mesurament yesterday. pH depends on the temperature of your sample and they said that the pH must always be accompanied of the temperature at what you did the analyse. They also said that you don't "compensate", the device is giving you the pH at that particular temperature (I thought that the pHmeter compensates temperature, I was wrong). So the best thing to compere pH values of a product is to analyse always at the same temperature. 



carine

    Grade - SIFSQN

  • IFSQN Senior
  • 338 posts
  • 22 thanks
5
Neutral

  • Earth
    Earth

Posted 03 June 2020 - 03:09 PM

No, just water itself, nothing was added. 

Yes.  Is there anything in the ice by chance?  Or just water?  If you have other things, additives, flavors, etc you can get different pH readings due uneven distribution and the measurement only able to test the surface.

 

If it isn't an issue I'd melt the ice before testing.  It will give you a more repeatable and representative pH.  Make sure to use an probe with ATC compensation.



Charles.C

    Grade - FIFSQN

  • IFSQN Moderator
  • 19,083 posts
  • 5312 thanks
1,273
Excellent

  • Earth
    Earth
  • Gender:Male
  • Interests:SF
    TV
    Movies

Posted 03 June 2020 - 03:16 PM

Looks like an old problem being resurrected ?

 

https://www.ifsqn.co...be-ice-product/

 

https://www.ifsqn.co...on/#entry152614


Kind Regards,

 

Charles.C


Thanked by 2 Members:

Setanta

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,273 posts
  • 313 thanks
255
Excellent

  • United States
    United States
  • Gender:Female
  • Interests:Reading: historical fiction, fantasy, Sci-Fi
    Movies
    Gardening
    Birding

Posted 03 June 2020 - 06:55 PM

I guess they didn't like the answers in December


-Setanta         

 

 

 


Ryan M.

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,261 posts
  • 456 thanks
258
Excellent

  • United States
    United States
  • Gender:Male
  • Location:Birmingham, AL
  • Interests:Reading, crosswords, passionate discussions, laughing at US politics.

Posted 04 June 2020 - 12:08 AM

It sounds like you are monitoring pH to meet a regulatory requirement which states "water" with pH in the range.  Doesn't tell you what state the water has to be in...gas, liquid, solid.  As such, make your life simple and melt the ice before you conduct your testing.  If you can, melt to a consistent temperature so all testing is at that same temperature.



pHruit

    Grade - FIFSQN

  • IFSQN Fellow
  • 1,867 posts
  • 737 thanks
447
Excellent

  • United Kingdom
    United Kingdom
  • Gender:Male
  • Interests:Composing/listening to classical music, electronics, mountain biking, science, sarcasm

Posted 04 June 2020 - 08:05 AM

Dear pHruit, 

 

In our country raw water and ice shared same standard under the food act, in other words, pH for raw water n ice will be the same which is 6,5-8.5  . To me not a big deal if pH of the product out of spec, but  from local authorities view , our finished product is not comply to the law, and we have to take corrective action on this. 

 

So is the water itself coming in at 6.5-8.5 but then once you've frozen it to produce the ice then thawed it to test, it's no longer in this range?
Or is it the case that the water isn't always between 6.5-8.5?

 

For the former, it suggest there is possibly something else happening to the water during the freezing process - e.g. contamination with an acid/alkali of some sort. Possibly wouldn't need to be significant quantities as the water itself won't have a large buffering effect.

 

For the latter it suggest the issue is really a raw material one, and you'd really then need to look at your water source in more detail.






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users