Volatile Acidity (VA)
The presence of volatile acids in wine — primarily acetic acid — which at high levels produces an unpleasant vinegar or nail-varnish smell and is considered a wine fault.
In depth
All wines contain some volatile acidity — it is a natural by-product of fermentation. At low levels (below 0.6 g/L for whites, below 0.8 g/L for reds typically), VA contributes complexity and is barely perceptible. At higher levels, acetic acid (the main volatile acid) dominates the nose with a sharp vinegar or acetone/nail-varnish smell, which is classed as a wine fault.
VA is caused by bacteria (primarily Acetobacter) converting alcohol into acetic acid when wine is exposed to oxygen. It can also develop when fermentation is sluggish or stuck, as yeast under stress produces more acetic acid. Ethyl acetate — the reaction product of acetic acid and ethanol — adds a nail-varnish aroma on top of the vinegar note.
Some winemakers deliberately allow very modest levels of VA in complex red wines, arguing it adds "lift" to the aromatics. This is particularly discussed in the context of natural wines and some traditional Italian reds.
At Level 3 wine faults, candidates must identify VA by smell (vinegar/nail varnish), name the cause (Acetobacter, oxygen exposure), and distinguish it from other faults such as TCA (damp cardboard) and reduction (sulphur/rubber).
Related exam topics
Frequently asked questions
- Is volatile acidity always a wine fault?
- At high levels, yes. But at low levels (below about 0.6 g/L acetic acid for white wines) VA is barely perceptible and is considered normal. Some winemakers of complex red wines deliberately allow modest VA as it can add aromatic lift. It only becomes a fault when it dominates the nose with a vinegar or nail-varnish character that detracts from the wine's quality.
Practise questions on this topic
Use Vinlecta to practise exam-style questions that test your knowledge of volatile acidity (va) and related topics.