Do I need a new pH meter?

My pH meter.

My pH meter.

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.

WTF?….

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About SUAMW

Father, husband, physician, amateur guitarist, wine lover, wine writer, wine grower and wine maker trying to do it all within eye shot of downtown Los Angeles. http://www.shutupandmakewine.com http://twitter.com/Dr_Arthur_P
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2 Responses to Do I need a new pH meter?

  1. Joy says:

    well, I am thinking perhaps CO2 during fermentation may cause the drop in pH, but probably not so much.
    However, in regard to your pH-meter, even if it is temperature-adjusted (pH is quite variable according to temperature), I would always try to get readings at a standard temperature. Best would be to have the buffers that you’re using to calibrate the instrument approxymately at the same temperature of the juice-must or wine you’re measuring.

  2. SUAMW says:

    Thanks, Joy

    The initial pH was done prior to fermentation and the follow ups were done when there was no visible CO2 bubbles. Not that that means there was no dissolved CO2. The calibration solutions were kept at the same temp as the wine – in the same room.

    The wine is pretty acidic to the taste – which was masked by sugar prior to fermentation.

    There is always cold stabilization and deacidulaion – as much as I don’t like to do that.

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