Argentum
Regular.
Question: If while using a pH meter with ATC I measure a mash pH sample directly within the mash while it is at 67 degrees C., and I get a reading of 5.20, and then I subsequently cool the very same sample down to 25 degrees C. and get a reading of 5.55 pH from the same meter, which reading is correct? And since my meter has ATC, why on earth should the readings appear be so vastly different?
1) Answer as to which reading is correct: Thanks to "ATC" both are assuredly 100% correct pH readings (presuming accurate and very recent calibration, and also presuming a high quality and well made pH meter).
2) Answer to why are the readings appear different: Because ATC does not do what 99.9% of us simply assume and/or take for granted (or wish) that it does. And because pH is inherently linked to temperature such that pH is both actually and factually demonstrably different at different temperatures. Lesson to be learned: Do not presume that ATC corrects pH readings for changing temperature such that at both 67 degrees C. and at 25 degrees C. the meters pH readings will be of the same value. All that ATC does is to correct the meters internal mathematics (and more specifically a slope function related to temperature) such that it can factually give you the actual pH that exists (albeit being inherently different) over a relatively broad range of temperatures. What it does not do is give you altered pH readings compensated for temperature such that the readings will come out looking to be the same and you won't need to be concerned with the sample temperature, such as likely 99.9% of us wish and/or presume that it does.
1) Answer as to which reading is correct: Thanks to "ATC" both are assuredly 100% correct pH readings (presuming accurate and very recent calibration, and also presuming a high quality and well made pH meter).
2) Answer to why are the readings appear different: Because ATC does not do what 99.9% of us simply assume and/or take for granted (or wish) that it does. And because pH is inherently linked to temperature such that pH is both actually and factually demonstrably different at different temperatures. Lesson to be learned: Do not presume that ATC corrects pH readings for changing temperature such that at both 67 degrees C. and at 25 degrees C. the meters pH readings will be of the same value. All that ATC does is to correct the meters internal mathematics (and more specifically a slope function related to temperature) such that it can factually give you the actual pH that exists (albeit being inherently different) over a relatively broad range of temperatures. What it does not do is give you altered pH readings compensated for temperature such that the readings will come out looking to be the same and you won't need to be concerned with the sample temperature, such as likely 99.9% of us wish and/or presume that it does.
