🍷 Acidity

Acidity (wine tartness, acids in wine) is the fresh bite that makes your mouth water. The main grape acids are tartaric and malic, together up to 90 percent of the organic acids. All acids make up under 0.7 percent of the juice, yet they govern both a wine's stability and its taste.

Ripening reshuffles them. Malic acid peaks at veraison, up to 25 g/L, and by harvest drops to 1 to 5 g/L. Tartaric hardly shrinks. The warmer it is, the faster malic acid breaks down. That is why, in many established regions, warming has pushed total acidity down and pH up.

Growers track titratable acidity (TA), pH and sugar. Near peak maturity TA and Brix level off. Yet what you taste follows pH more directly than TA. Two Italian grapes from Colli Piacentini show it well. Barbesino wine had TA of 5.04 g/L, Ortrugo 3.91. The pH differed too, 3.00 against 3.20. Malic acid made most of the gap: 2.96 against 1.02 g/L.

Each acid has its own page: Tartaric acid, Malic acid, Lactic acid, Citric acid and Acetic acid. For pH go to Wine pH, and for how acid sits with sugar and tannin see Wine balance. Cool climate and High-altitude vineyards also bear on acidity, as do Deacidification and Ageing potential. All of it belongs under Wine.