pp ) wrote:
>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

How soon after fermentation are you measuring? More to the point,
are you de-gassing your sample? Just today I had a sample of
riesling that finished fermenting in November read 1.1 g/L too high
because I forgot to de-gas it. And that's after multiple
filtrations, ulitmately through 0.7 micron pads.

Anyway, if you haven't degassed, try that.

Dave
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Dave Breeden