Wine fault
Unintended refermentation
A still wine that has started fermenting again in the bottle — fizzy when it should not be, and often cloudy with it.
What you notice
Smell
- Smells yeasty or of bread dough
Appearance
- The wine is hazy — also seen in Haze and cloudiness
Texture
- A still wine has a distinct prickle or fizz
What it is
A genuine fault, though a fairly rare one in commercially produced wine.
It needs disentangling from two harmless things. Some wines are bottled with a deliberate slight spritz — Vinho Verde, Muscadet sur lie, some Grüner Veltliner — and that is intentional. Others carry a faint prickle of dissolved carbon dioxide added at bottling to keep them fresh.
The distinguishing signs are cloudiness and a yeasty smell alongside the fizz. Intentional spritz comes with a clean, bright wine.
What causes it
- Residual sugar plus surviving yeast, in a wine that was not stabilised or sterile-filtered.
- Warm storage waking up dormant yeast.
- Malolactic conversion occurring in bottle when it was not intended.
Can I fix it?
No — nothing will fix it
No. Live yeast has restarted in the bottle and there is no way back.
What you can do
- Nothing can be done. Return it.
What does not work
Published because a reader holding a spoiled bottle has usually already been told to try one of these. Correcting the specific wrong advice is more use than stating the right answer beside it in silence.
- Letting the fizz out and drinking it flat
- The carbon dioxide is a symptom. The yeast activity that produced it has also changed the wine, and it will keep changing.
Is it safe to drink?
Harmless in itself — check the rest
This on its own is not a health concern, but it is worth checking for the other signs described below before pouring.
Usually, though it will taste wrong: a still wine that has refermented has simply had a second fermentation it was not meant to have, and the results are yeasty and spritzy rather than harmful. The exception is the bottle itself. Fermentation generates pressure, and a still-wine bottle is not built for it.
If a still wine is fizzing, the cork is being pushed out, or the bottle is bulging or leaking, do not force it open over your face and do not drink it. Pressure has built up inside, and the wine has been colonised by something other than what the winemaker intended.
Can I take it back?
Yes. This is a stabilisation failure.
Sources
Sources consulted
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