Acidity

What is Acidity? Acidity is the sharp, tart, mouth-watering sensation produced by various organic acids naturally present in wine. It is one of the fundamental structural components of a wine, balancing sweetness, tannins, and alcohol, and giving the liquid its freshness and lift. Winemakers measure it in two ways: by pH, where most wines fall between 2.9 and 3.9, and by total acidity (TA). A lower pH means a more acidic wine, though TA and pH do not move in a strict linear relationship.

The Acids Behind the Sensation

Three acids are inherited directly from the grape: tartaric, malic, and citric. Tartaric acid is the most prominent and the backbone of a wine's acidic structure, while malic acid is the second most common grape-derived acid. Malic levels can peak as high as 20 g/L before veraison and then drop to roughly 1 to 9 g/L by harvest, especially in warmer climates where respiration burns it off.

Additional acids appear during winemaking and fermentation, including acetic, butyric, lactic, and succinic acid. During malolactic fermentation, sharper malic acid is converted into softer lactic acid, which is why many reds and barrel-fermented whites feel rounder on the palate. Winemakers may also work with auxiliary acids such as ascorbic acid (vitamin C), sorbic acid, and sulfurous acid for stability and preservation.

Fixed and Volatile Acids

Wine acids are divided into two groups. Fixed acids — tartaric, malic, lactic, citric, and succinic — stay in the wine and shape its taste and structure. Volatile acids, primarily acetic acid, can evaporate and, when present in excess, signal the fault known as volatile acidity (VA). Most tasters can detect VA at concentrations around 600 mg/L, where it begins to smell of vinegar or nail polish.

Beyond flavor, acidity does serious structural work. It stabilizes pigments and contributes to color, protects the wine from spoilage, and underpins ageing potential — wines without enough acid tend to taste flabby and fade quickly in the bottle.

How Acidity Tastes

On the palate, acidity registers as a prickling sensation along the sides of the tongue, followed by a mouth-watering aftertaste that makes you want another sip. This is the same reflex that makes acidic wines so effective at cutting through fat and salt, which is why crisp whites pair so naturally with seafood and creamy dishes.

In a well-made wine, acidity is felt rather than tasted in isolation. It pushes against sweetness, frames the fruit, and keeps tannins and alcohol from feeling heavy. When the balance is right, a wine feels lively and precise; when acidity is low, it feels soft and dull; when acidity dominates, it tastes sour and thin.