Testing pH Acidity Using Litmus Paper

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Chuckwagon
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Testing pH Acidity Using Litmus Paper

Post by Chuckwagon » Sat Aug 06, 2011 11:59

Testing pH Using Litmus Paper

U.S. Government FSIS meat inspectors and professional commercial sausage makers use battery powered devices for measuring the acidity (pH) in meat as well as Water Activity (Aw) during dehydration. The PawKit (for testing Aw) is a quality-made product by Decagon Devices Incorporated in Pullman, Washington. (www.decagon.com). It weighs only 4 ounces and is incredibly accurate. However, the last time I checked the price of a PawKit water activity meter, it was over three hundred dollars!

To test the acidity level (using the pH scale) in meat, a Hanna pH test meter is available from Hanna Instruments in Woonsocket, Rhode Island. (www.hannainst.com/usa). I don't know the price of this item but you may view it by clicking on this link: http://www.eutechinst.com/products/portables/ph56.htm

Home hobbyists, needing a convenient and inexpensive method of testing pH acidity in sausage, have found a product called "pHydrion Microfine Testing Strips". The product is available from any pet store that sells fish or most sausage equipment suppliers for about $12.99 for a dispenser of 15 feet of litmus paper testing paper strips. The product is available in two ranges, first for testing acidity from 3.9 to 5.7 pH, and second, for testing acidity from 4.9 to 6.9 pH. Testing is done by color comparison and although the results may be less accurate than an electronic PawKit can provide, test strips are a bargain at about 6 cents per test!

To test, mix 1 part chopped meat with 2 parts distilled water, tear off an inch of testing paper, dip it into the solution, and match it to the color chart on the side of the dispenser. No technical training required!

Best Wishes,
Chuckwagon
Last edited by Chuckwagon on Thu Jul 05, 2012 12:59, edited 1 time in total.
If it looks like a duck, walks like a duck, and quacks like a duck, it probably needs more time on the grill! :D
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Bubba
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Post by Bubba » Sat Aug 06, 2011 12:57

Hi Chuckwagon,
I have been searching for a pH meter for my home projects, and this advice from you is very handy as well as budget friendly information.

It's what makes this site so amazing, I have been spending a lot of time reading and learing from past postings on here.

Thank you again,
Bubba
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Post by two_MN_kids » Wed Oct 29, 2014 16:24

Last Sunday, planning for a summer sausage, we mixed salt and cure with 16# of diced beef, and salt into about 2# of back fat. Yesterday, we ground the meat and mixed in the remaining ingredients, including Bactoferm F-LC. After mixing, I tested for pH with pHydrion Test Strips. I have two strips; one measures from 3.9-5.7 and the other from 4.9-6.9.

I had expected a similar reading from both strips. The first gave a max reading of 5.7, but the second appeared to be just wet. It matched the color sample for 4.9 on the low end. I had expected a mid-range reading of 5.7 or higher.

I thought I should test the strips somehow. I mixed a pinch of baking soda with ¼ tsp water. Both test strips turned color. The lower reading strip turn Indigo blue while the higher reading strip turned Purple. Of course, neither color was on the charts, but I verified they work.

After sixteen hours of fermenting, the meat sample tested at pH 5.4, so the sausage is going in the right direction.

Very confusing!
Jim
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redzed
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Post by redzed » Wed Oct 29, 2014 16:52

Hi Jim!

Yeah, testing with strips can be a challenge, especially for a guy like me since my wife claims I'm colour blind! The difference might be because one sample might have had more fat than muscle tissue and the ingredients also might have affected the reading. It is best to assess the starting pH of the meat just after grinding and before you add the spices. When I take a reading with my meter I also never get the exact same result. I use a custard dish with a meat sample that I check throughout the process. So when I test with the probe in three places, each reading is usually different, although the differences are not that wide. I note the average of the three in my journal.

And I'm assuming that you are using two parts distilled water and one part meat to test? Check the pH of the distilled water. It should be 7, neutral for acid. If it is not, then that can also skew your readings. I distill my own water (and hooch, but that is another story :grin: ) and can never get it to read 7.
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Post by Bob K » Wed Oct 29, 2014 17:03

After mixing, I tested for pH with pHydrion Test Strips. I have two strips; one measures from 3.9-5.7 and the other from 4.9-6.9.

I had expected a similar reading from both strips. The first gave a max reading of 5.7, but the second appeared to be just wet. It matched the color sample for 4.9 on the low end. I had expected a mid-range reading of 5.7 or higher.
Jim-
The ph on the 3.9-5.7 strips showed that the ph was over 5.7
On the second strips 4.9-6.9 range, should have changed.

The starting Ph is usually in the mid to high sixes for many meats.

The most important reading was the drop you had to 5.4 as that showed the culture was working. Did you check that reading with both type strips?

Did you mix the sample with water to test? If so always check the Ph of the water before mixing, it should be close to 7.0 for an accurate test.
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Post by two_MN_kids » Wed Oct 29, 2014 17:22

Bob, I mixed the meat sample with bottled distilled water at ratio of one part meat and two parts water. Using the distilled water, I didn't test the pH as I assumed it at 7.0.

Both strips were used to test the meat pH, but only the one registered. As I also expected both strips to react, have to wonder if manufacturer mislabeled the container. Unsure how to test for range.

Jim
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Post by redzed » Thu Oct 30, 2014 15:59

two_MN_kids wrote:Bob, I mixed the meat sample with bottled distilled water at ratio of one part meat and two parts water. Using the distilled water, I didn't test the pH as I assumed it at 7.0.

Both strips were used to test the meat pH, but only the one registered. As I also expected both strips to react, have to wonder if manufacturer mislabeled the container. Unsure how to test for range.

Jim
Jim, if you really want to see whether the strips are working, buy a couple bottles of calibration solution. They come at 4.0 and 7.0 readings and will cost you about ten bucks for both. I buy mine at a hydroponics store. Another factor to consider when testing is that temperature will also make a difference. A neutral solution will read 7.0 at 25°C, 7.47 at 0°C and 6.63 at 50°C. pH meters are able to adjust for the temp, but the strips do not. So if you are testing very cold meat your reading will be slightly elevated.
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