Question about technique for pH testing

I don't see how the amount of tartaric you added could have lowered the pH that much. You might try removing a test size sample of the wine and allow to set for awhile, recalibrate your pH meter and re-test.

When I first tested the must after adding the acid, it tested

3.38-3.40, which I was happy with. It tasted acidic. But the only reason I can think of that the pH rose that much was because of all of the dissolved CO2. I seem to remember that one should heat up a sample before testing, to drive off the CO2.

This was discussed in the past so you might want to search the archive for more details. From what I remember, pH should not be affected (much), TA is. The heat treatment is needed for measuring TA. But you can always do this and measure the pH as well to take one variable out.

I agree with Paul that the drop is too big. Normally the pH tends to go up doing the ferment as potassium from the skins gets extracted into the juice. So it does seem strange it'd go from 3.4 to 3.2.

Finally, you can't really do much at this point anw, so perhaps the best option is just to wait, do the ML, naybe cold stabilize and see where you end up. You can always take out some acid chemically if necessary but the wine will probably be fine.

We always tend worry a lot about our "babies" when they're taking their first steps; they're usually turn out just fine on their own...

Pp

Great advice, wait it out is what I would do too.. From what I have read, pH is not affected by CO2 but that seems silly; I always take 50 ml of sample, bring it to a boil in a microwave, let it cool, add distilled water to bring the value up to 50 ml again. I need to do that for TA anyways so just use that sample for pH too. pH can go down due to fermentation, other acids are formed.

Joe