Ph measures the strength of the acid no matter how much acid is in the
must and TA gives you the total amount of acid. I'm no expert but if
you had a small amount of a really strong acid you could have a PH that
was lower ( more acidic ) than if you had a larger amount of a weaker
acid. Say theoretically, and I'm not sure this is true , but say after
MLF there is the same amount of lactic acid as there was malic acid ,
the PH will rise due to the same amount of weaker lactic acid, the TA
would stay the same but the PH would rise. There are alot of winemakers
out there, myself included, that never even take TA readings. The only
important reading BEFORE fermentation is the PH. After fermentation ,
adjustments are made by taste and not by what a scientific measurement
will tell you. After making enough wine and tasting it year after year
and comparing it against store bought , you get a feel for what you
want and need to do. I usually will take more PH measurements after
tasting but that is just for a FYI. BTW, you should take the PH's of
store bought wine after you taste them to sharpen your tasting skills.
This is just my method. There are others out there that swear by the TA
including Jeff Cox , author of From Vines to Wines.

Bob


wrote:
> What is the difference and why use them both? When I first began
> making wine I was under the impression that they both told the same
> story.