The backbone of balance; acidity is one of the most important - and most misunderstood - elements in wine. We've asked Assistant Winemaker, Gareth Hogan, to offer some expert guidance in navigating these subtleties.

While the word 'acid' can sound harsh, in wine it is essential. Without it, wine would taste flat, heavy and lifeless. Quite simply, acidity is what makes your mouth water. It creates that refreshing, zippy sensation that brings energy to a wine and can elevate food alongside it.

The Acids in Grapes

The primary acids in wine grapes are tartaric and malic acid. Wine grapes contain more tartaric acid than any other fruiting plant - so much so that its presence in ancient pottery is used as evidence of early winemaking.

Malic acid, also found in green apples, is sharper in character. During malolactic fermentation, it can convert into softer lactic acid, changing a wine’s texture from crisp and linear to creamy and round. This is why some Chardonnays show bright citrus drive, while others display a fuller, more supple palate.

Beyond these two, smaller amounts of citric and succinic acid also play subtle roles, contributing nuance and complexity. Though less prominent, they can influence a wine’s aromatic lift and the gentle savoury edges that emerge with age.

Balance and Structure

As grapes ripen and sugars rise, acidity falls. This natural see-saw is one of the most critical decisions in harvest timing, as acidity regulates many of the wine’s chemical and sensory components.

Acidity creates balance among fruit, alcohol, tannin and sugar. Without it, ripe flavours can feel heavy or cloying. Like a squeeze of lemon in cooking, acidity sharpens and lifts.

It also provides structure, particularly in white wines, giving shape and direction to the palate. High-acid wines feel focused and precise; lower-acid wines feel broader and softer. In sparkling wines, pronounced acidity is even more essential, forming the spine that supports effervescence and ensures the wine finishes clean and dry rather than sweet or diffuse.

Ageing and Climate

Acidity is key to longevity. Acting as a natural preservative, it allows wines to age and evolve while maintaining freshness. Over time, as primary fruit notes mellow and secondary characteristics develop, acidity keeps the wine vibrant and defined.

Climate strongly influences acid retention. Cooler regions preserve acidity through slower ripening, while warmer climates see acids decline more rapidly as sugars accumulate, requiring careful management to maintain balance. Vineyard practices such as canopy management, site selection and picking decisions all play a role in protecting this vital component.

In the end, acidity is the element that keeps wine vibrant - the quiet architect behind poise, precision and drinkability. If a wine feels lively and refreshing, acidity is doing its work.