Yesterday, instead of making a batch of cheddar as planned, I thought I'd go with some Edam. Everything looked great all the way through brining. Today when I took it out of the brine the ph level was 3.4! Ph levels looked great at every phase, (going from 5.9 to 5.5) the brine ph was matched to the pressed wheel (5.5) just before it went into the brine. Any ideas?
Test again?
I doubt that it could be as low as 3.4. I don't think that there is enough lactose in milk to take it this low and the lactic bacteria likely die somewhere around a pH of 4. I agree with stinky. Make sure the probes on your meter are clean (cheese contains fat and fat waterproofs the probes causing erroneous readings). Use mild dish washing detergent, rinse well and dry. Also be sure your meter is calibrated. You do have some buffered testing solution, right? Here's what I use. (http://www.amazon.com/Atlas-Scientific-Calibration-2-Piece-Solution/dp/B0157DOYZ6/ref=sr_1_3?s=industrial&ie=UTF8&qid=1455602114&sr=1-3&keywords=ph+calibration+solution)
Usually when making brine, you add vinegar to bring the pH to the approximate level of the cheeses that will be brined. If you got too much vinegar, perhaps your brine pH is low ... and what you are reading is either a bit of brine still on the surface, or perhaps the outer surface of the cheese dropped that low under the influence?
All of this is just guessing on my part, but I'd say step one will be to do as Kern says -- make sure your probe is clean and calibrated -- then step two is to test the pH of your brine.
Ok, I calibrated my meter, checked it again, it read 4.3, so I used a strip just to see if it showed something really different. Nope, its was right in there, it read a 4. Seems weird to me that it fell so low in 12 hours. It doesn't appear to have an alien bacteria. I guess I'll let it get good and dried out, wax it and see what I end up with in a couple months.
I would not be surprised that the pH read by your meter continues to climb over the next several weeks. The only "real" way to measure it now would be to take out a sample of the paste with a trier and "squish" some paste over the meter probes. If you put the cheese in 55F brine at a pH of 5.3 or so the true pH is likely no lower than 5.1. Sampling becomes very important once you start measuring cheese curds and paste.