Understanding acidity levels in wine

When someone says a wine has ‘high acidity,’ they’re talking about a zingy, crisp, fresh quality that makes each sip lively and balanced. Acidity in wines like Riesling or Pinot Noir plays a vital role in defining their flavour. It highlights the fruit flavours, adds structure and provides a refreshing finish.

What is acidity?

That refreshing, crisp feeling on your tongue when you drink wine is acidity at work. This fundamental element does more than create a tart impression – it’s the backbone of a good wine’s structure.

Several factors determine a wine’s natural acid profile, including the grape variety’s characteristics, the climate conditions of the vineyard, the timing of the harvest and the winemaking techniques used during production.

Main acids from grapes:

• Tartaric acid – The most critical and dominant acid in wine, giving it its distinctive tartness.

• Malic acid – This adds a refreshing, crisp sourness that reminds some people of a green apple.

• Citric acid – Naturally present in smaller amounts, this adds citrusy freshness. Winemakers might also add a touch more to boost acidity when needed.

Acids formed during winemaking:

• Lactic acid – Created during malolactic fermentation, provides a softer, creamier mouthfeel

• Acetic acid – In small amounts, it contributes to complexity, but too much creates vinegar notes

• Succinic acid – Formed during fermentation, adds a savoury, slightly salty dimension

The balance of these acids significantly impacts a wine’s taste, ageing potential, and overall quality.

How does wine get its acidity?

While grapes provide the foundation of wine’s acidity, two critical factors decide the acid profile in your glass:

Where the grapes grow

The growing environment has a significant impact on grape acidity.

• Warm regions - Grapes ripen quickly in Australia’s warmer regions, such as Barossa Valley or McLaren Vale. This means less acidity but more sugar, creating wines with richer fruit flavours and softer acidity.

• Cool regions – Vineyards in cooler regions like Tasmania or Adelaide Hills produce fruit that ripens gradually, keeping more natural acidity. This is why cool-climate wines often taste refreshing.

What the winemakers do

Winemakers can adjust acidity in several ways. Malolactic fermentation (MLF) is one of the most essential techniques. During this process, bacteria convert sharp malic acid (like green apple tartness) into gentler lactic acid (like the softness in milk).

This reduces overall acidity in wine but also introduces texture, adding creaminess to wines like Chardonnay or softening structured reds. It also adds subtle buttery flavours.

Finding the right acidity level is tricky. Too little makes wine taste flat and dull, while too much makes it uncomfortably sour. A skilled winemaker knows how to hit the sweet spot for a balanced, enjoyable wine.

How to tell if a wine is acidic

Wine acidity affects how your wine tastes and feels in your mouth.

High-acid wines taste crisp, like biting into a fresh apple. Low-acid wines feel smoother and rounder.

Want to check a wine’s acidity? Take a small sip and notice if your mouth waters more than usual. If it does, the wine has high acidity.