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Jul 15, 2007 08:17 PM

pH tester for food?

Does anyone know of a decent probe-style pH tester good for food use? I see a lot that are mostly for soil or pool/spa, but not sure if I should get one dedicated for food use?

The only thing I could see online was this Hanna instruments one
I mostly want it for sourdough making, cheeses, etc.


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  1. The problem with anything that you'd want for food use is that the nature of pH electrodes relies on permeable glass, so you HAVE to get an isolated and replaceable electrode. The keep type with the permanently attached electrode probably would be useless in cheese making. I am not sure if any hobby type meter is going to be very useful in the bread making, as they all rely on a large amount of water/aqueous phase mixture for their reading...

    1. HI, I was a recipe tester for Peter Reinhart's whole-grain book coming out soon, and he recommended using pH papers to test sourdough starters. You'd want the papers that go from 3.0 to 5.5, such as those in the top group here:

      6 Replies
      1. re: bakergal

        Interesting. So it's back to the paper, eh?! I guess I just figured that if I used them in high school chemistry, they were probably an inferior way to test. I guess not.

        What do you think about this guy's method and probe tester? (renov8r, in particular, your comment about the permeable probes is interesting in light of this)

        (note the pictures to the right)

        1. re: adamclyde

          omigawd -- that seems like a way to really break an innocent pH meter.

          I was actually a biochem major in college, so I used to work with a lot of lab equipment. The baker from the website has basic principle of pH correct, that H+ ions will be present in the aqueous phase. The problem is that by ramming a solid up against the electrode it is very likely to be destroyed. Further the effect of CO2 gas or an individual bit of unmixed something or other from the bread can totally through off the reading.

          Now if you were building a factory that needed a remote sensor for a "slurry" of bread dough moving past in a vat or pipeline you could get something like this:

          And folks have done research to prove that this can be reliable/repeatable in bulk:

          BUT for a home baker I have to think that test paper is a better option

          1. re: renov8r

            alas it seems like you are right. I was actually not worried about trying to test the bread as a final product, but rather the sourdough liquid, which wouldn't require as much fiddling with the equipment. So a probe seemed to work well. But, I didn't know about the whole permeability of the stuff and all. Regardless, it seems like paper is the easy solution here. Thanks all for the help.

            1. re: adamclyde

              I just want to clarify --

              Reinhart said to aim for a pH of 3.5 to 4.0 for the refreshed starter, and

              To use the paper, tear off a few inches and spoon a drop of starter, dabbing it onto the test paper, immediately noticing the color change. Don't dip the paper into the starter itself.

              I'm sure you both know this, but others reading this may be unsure.

              1. re: bakergal

                actually, no, I didn't know! I would have stuck the paper into the starter itself. so thank you.

                on that point, when you say aim for 3.5 to 4, are you saying it's at that point where your starter is ready to make bread, or that's when you refresh it?

                1. re: adamclyde

                  Well, I would have done it wrong, too, had I not read the instructions!

                  If I understand it correctly, 3.5 to 4 is the point at which the starter is ready to make bread. To quote PR: "It may not double in size but if it reaches the proper acidity it is ready. If the starter has accomplished this before you are ready to make the final dough, place it in the refrigerator... You can also use the taste test: it should taste tangy."

                  I've gotten away from the papers -- too lazy I guess, or afraid the starter won't be ready when I am. So I taste it and if it seems reasonably sour, I continue. I'm just looking for bread, not a science project.