Wine Fault

Oxidation

Chemical

Oxidation occurs when wine absorbs excessive oxygen, shifting color toward brown or brick tones and developing nutty, caramel, or bruised-apple aromas. Some styles embrace controlled oxidation; unplanned oxidation is a fault in most table wines.

Also known as: Oxidized wine, Oxygen spoilage, Aerobic spoilage

Typical severity: Medium

Cause

Excessive oxygen exposure accelerating aldehyde formation and browning reactions in wine.

How it occurs

Permeable closures, ullage in aged bottles, leaky barrels, excessive racking, and poor cellar temperature accelerate oxidation. Low SO₂ and high pH wines are especially vulnerable.

Prevention

Maintain adequate free SO₂, minimize headspace, use inert gas during transfers, store cool and dark, and choose appropriate closures for intended aging.

Descriptors created

Descriptors reduced

Commonly confused with

Common wine styles

Common grape varieties

Common regions

Related winemaking techniques

Serving implications

Beginner explanation

Oxidized white wine turns deeper gold or brown and smells nutty or like dried apple — different from intentional Sherry oxidation.

FAQ

Can oxidation be reversed?
No — once aldehydes and browning develop, oxidation cannot be undone. Young oxidized wines may improve slightly with time but remain altered.
Is all oxygen bad for wine?
Small controlled oxygen during barrel aging aids integration. The fault is unplanned, excessive exposure that overwhelms fruit.

Related ontology entities

See also

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