Wine Fault

Refermentation

Physical

Refermentation happens when residual sugar or malic acid ferments in bottle, creating unintended spritz, turbidity, and off-aromas. It can push corks and indicates incomplete stabilization before bottling.

Also known as: Secondary bottle fermentation, Fizzy fault, Bottle ferment

Typical severity: High

Cause

Yeast or bacteria fermenting residual sugar or malic acid in bottle under warm conditions after an incomplete sterile bottling.

How it occurs

Bottling with residual sugar and viable microbes, insufficient SO₂, or incomplete MLF allows slow in-bottle fermentation. Warm storage accelerates the process.

Prevention

Ensure fermentation completeness, sterile filtration when appropriate, adequate SO₂ at bottling, and cold stabilization of microbial loads.

Descriptors created

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Commonly confused with

Common wine styles

Common grape varieties

Common regions

Related winemaking techniques

Serving implications

Beginner explanation

Unexpected fizz in a still wine — especially with haze or pushed cork — usually means refermentation, not intentional pét-nat.

FAQ

Is refermentation dangerous?
Rarely a health risk in table wine, but pressure buildup can break glass. The wine is organoleptically faulty regardless.
How is this different from pét-nat?
Pét-nat is intentional ancestral-method sparkling. Refermentation is unplanned microbial activity in a wine meant to be still.

Related ontology entities

See also

Fault identification guidance reflects common wine education practice and may vary by wine style, age, and context.