I spent a hundred bucks on my pH meter. I expect it to be reliable.
I’m pretty careful with my equipment and try to keep it clean and in good repair. I calibrate my pH meter before each use.
When I crushed the Fiano, I adjusted t he pH to 3.2. At crush, the Montepulciano was 3.45.
When checked in on my wines recently, I got a few surprises:
My Fiano tastes clean, tests 1% RS with Clinitest and the pH registered 3.04… The Montepulciano registered “trace” to 1/4% RS by Clinitest and 3.23 pH…
The pHs could not have dropped that much during fermentation. I calibrated the meter twice and got the same pH readings, although just after calibration, the meter would read the the calibration solutions slightly off (by a few hundredths of a point – so the 4.01 pH solution was registering 3.98).
I went to The Home Wine, Beer and Cheesemaking Shop in Woodland Hills where they have a table-top Hanna pH meter in the back. My readings were confirmed.
As I said earlier: I’m careful with my equipment and calibrate my meter obsessively.