Acidity is one of the main elements that makes wine taste fresh, bright and balanced. Too little acidity can make wine taste flat, soft or overly sweet. Too much acidity can make wine sharp, sour or difficult to drink.

Getting acidity right is not about chasing one perfect number. It is about creating balance between fruit flavour, sugar, alcohol, tannin and body.

Why acidity matters in wine

Acidity influences:

• Freshness and brightness
• Perceived sweetness
• Colour stability in red wine
• Microbial stability
• Ageing potential
• Overall balance

A wine with the right acidity feels lively and clean. A wine with poor acidity can feel dull or harsh, even when everything else is right.

pH vs titratable acidity

Two measurements are commonly used in winemaking:

pH measures the strength of acidity and affects colour, stability and microbial risk.

Titratable acidity (TA) measures the total amount of acid that influences how tart the wine tastes.

Both matter, but they are not the same thing. Two wines can have a similar pH but taste different because their total acidity is different.

For practical home winemaking, a wine acid test kit can help you assess whether the juice or wine may need adjustment.

Wine Testing Equipment

When should you adjust acidity?

The best time to assess acidity is before fermentation, while the wine is still juice or must.

You can also make adjustments after fermentation, but changes are usually easier to manage earlier in the process.

Consider checking acidity when:

• You are using fresh grapes or juice
• Fruit tastes very sweet and low in brightness
• Your wine tastes thin or dull
• Your wine tastes harshly sour
• You are planning to backsweeten a finished wine

How to increase acidity in wine

If your wine tastes flat, overly soft or overly sweet, adding acid can improve balance.

Common wine acids include:

• Tartaric acid
• Malic acid
• Citric acid
• Acid blend

Tartaric acid is often preferred for grape wine because it is naturally associated with grapes and contributes a clean, wine-like acidity.

Add acid gradually. Dissolve it first, mix thoroughly and taste after each small adjustment. It is much easier to add more acid than to remove too much.

How to reduce acidity in wine

If a wine is too sharp or sour, there are several options depending on the cause.

Cold stabilisation

Chilling wine can encourage tartaric acid crystals to form and settle out. This can slightly reduce acidity and improve stability.

Blending

Blending high-acid wine with lower-acid wine or juice can soften the overall profile.

Chemical deacidification

Certain winemaking products can reduce acidity, but these should be used carefully and according to the manufacturer’s instructions.

Backsweetening

A small amount of sweetness can balance acidity, but the wine must be stabilised first to prevent renewed fermentation.

How to Stabilise Wine Before Backsweetening

Avoid making adjustments by taste alone

Taste is important, but it can be misleading when wine is very young, cloudy or actively fermenting.

Use measurements as a guide, then use tasting to make the final decision. Record every adjustment so you can repeat successful batches.

Frequently asked questions

What does low acidity taste like in wine?

Low acidity often makes wine taste flat, soft, heavy or overly sweet.

What does high acidity taste like in wine?

High acidity can taste sharp, sour, tart or thin. In some styles, high acidity is desirable, especially in crisp white wines.

Can I add acid after fermentation?

Yes, but add it slowly and taste regularly. It is usually easier to make larger corrections before fermentation