Hi:

I've been having a pretty consistent problem with titrating white
juice before fermentation, adding tartaric acid based on the results,
and then titrating after fermentation that the TA level is way too
high. Latest example: Pinot Blanc juice measured at 4g/L, acid added
to raise to 6.5g/L, now measured at 8g/L after relatively cold (around
15C) fermentation. I really don't know what's going on because:
- I'm using the same method (pH meter to 8.2) before and after
fermentation;
- the juice is fresh, so all acid should be measurable before
fermentation;
- it can't be sodium hydroxide losing strength because then the
measurement would be artificially higher, not lower;
- the error seems to be consistent, so that cancels any possible
accidents, like wrong sample size.

I'm stumped at this point, and I'd really appreciate any help on this,
as I don't enjoy wines that are too heavy on acid.

Thx,

Pp