Ask Wine Wizard

Affects of Acid

TroubleShooting

Kerry Kirkham — Oakland, California asks,
Q

How do TA and pH Affect flavor and mouthfeel in wine? Can that change in the bottle over time? And is this data useful to the consumer when printed on a wine’s back label or sell sheet?

A
In general, I think of how TA (titratable, or total acidity) and pH impact flavor and mouthfeel in this simple (and yes, perhaps simplistic) way: TA determines how tart or sour a wine tastes while pH points to how a wine feels in the mouth. TA and pH typically won’t change in the bottle over time, unless you had a lot of residual sugar or residual malic acid and then had a refermentation in the bottle. If the wine is unfiltered it’s technically possible that spoilage microbes could engage in enough metabolic activity where they might be consuming acids or sugars and excreting by-products. A great example of this would be if there was residual malic acid in a wine and then malolactic bacteria had a feral fermentation in the bottle. This would certainly raise the pH of the wine, as lactic acid is roughly half as “acidic” as malic acid. It’s hard to say whether consumers really benefit from having a wine’s pH and TA listed on the back of wine labels (or on wine lists). I would wager