"danno" > wrote:

> What is the difference between TA and pH? I have a chem degree some a
> technical answer is welcome. I haven't measured pH yet as my meter needs
new
> batteries.

TA is the percent by weight of acid in solution, expressed in terms of
tartaric, i.e. grams tartaric / ml solution * 100, or grams tartaric per 100
ml. solution.

[From the ph faq]

pH is related to an acid's strength in wine, while the TA relates to the
amount of acid. Although interrelated, they are not the same thing. A
solution containing a specific quantity of a relatively weaker acid such as
malic acid will have a different (higher) pH than a solution containing the
same quantity of a stronger acid such as tartaric.

The pH of a solution is defined as the -log of the hydrogen ion. Given the
measurement is logarithmic in nature, a solution with a pH of 3.0 is ten
times stronger than a pH of 4.0. The total quantity of hydrogen and
hydroxyl ions is constant in a solution, as one increases the other
decreases. Acidic solutions contain more hydrogen ions than hydroxyl ions;
basic solutions contain more hydroxyl ions than hydrogen ions. A pH of 7 is
neutral (neither acid or base) as the concentration of hydrogen ions and
hydroxyl ions are equal at that point.

HTH