Ph and TA difference

Hi Danno

TA is a measurement of the amount of acid in your sample usually stated as a ratio of ml/L. When you measure pH you are measuring the strength of those acids.

Regards

Frank

Since you have a chem degree, you know pH is a measure of the Hydronium ion concentration in solution (H20 + HX H3O+ + X-). The pH is highly subject to the buffering action of the other substituents in the wine (potassium salts, etc). The TA number (titratable acidity) is a measure of how many acidic protons can be neutralized with NaOH, but it refers to a standard. Typically, the TA 0.60-0.70 referes to the percent of tartaric acid (2 equivalents of H+) present in the wine. Some standards use H2SO4 as the standard the TA is related to. Sometimes you will see TA represented as percent, and sometimes as g of the specific standard acid per L.

Go to Jack Keller's site. He has a pretty good description.

Ray

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.

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

Great. Thanks! Jack explained the two quite well and I can now move on to my next question for which I will create a new topic.

-Danno