Many home winemakers believe the tart taste of juice or wine is directly
related to pH. However, research suggests this is not the case. The tart
taste of wine is more related to titratable acid (TA) and only indirectly
related to pH. Perhaps this is why tasting the juice or wine seems more
important than measuring either TA or pH.

Margalit in "Concepts in Wine Chemistry," page 299, states ............the
major factor in acidity taste is the TA, and the pH is just a minor
correction."
Here are some other references:
Amerine, M.A. et al. - Acids and acid taste; The effect of pH and titratable
acid" - Am. J. Enol. Vit. 16 (1965) 29.
Nagel, C.W. & McElvain, J.R. - "An analysis of the influence of pH and
titratable acid in the scoring of wine" - Am. J. Enol. Vit. 28 (1977) 69.
Noble, A.C. et al. - Comparison of sourness of organic anions at equal pH
and equal titratable acids" - J. Sensory Studies 1 (1986) 1.