Micro-Oxygenation
A controlled winemaking technique that introduces tiny, measured doses of oxygen into wine in a tank to soften tannins and stabilise colour — mimicking the slow oxygen exchange that occurs naturally in barrel ageing.
In depth
When wine ages in oak barrels, oxygen enters slowly through the barrel staves and around the bung, promoting polymerisation of tannins (making them softer) and stabilising colour pigments. Micro-oxygenation (MOX) replicates this effect in stainless steel tanks by bubbling small, precisely controlled amounts of oxygen through a diffuser stone.
The technique was developed in Madiran, France, in the 1990s to soften the notoriously harsh tannins of the Tannat grape variety without the expense of barrel ageing. It spread globally and is now widely used as a cost-effective tool for tannin management.
At high doses, MOX can accelerate ageing and reduce primary fruit character. At low doses it softens tannins and integrates colour without noticeably affecting flavour. It is considered a winemaking shortcut by critics, particularly natural wine proponents.
At Level 3, micro-oxygenation is discussed alongside other oxygen management techniques (barrel ageing, racking into open vessels) as a way of controlling tannin and colour evolution.
Related exam topics
Frequently asked questions
- Is micro-oxygenation the same as letting wine breathe in a glass?
- Not really. Letting wine breathe in a glass or decanter exposes it to relatively large amounts of oxygen all at once — useful for softening young tannins quickly before drinking. Micro-oxygenation during production introduces tiny, controlled doses of oxygen over weeks or months during tank ageing, more closely mimicking the gradual, slow oxygen ingress of barrel ageing. The goal in production is long-term structural change, not immediate softening.
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Practise questions on this topic
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