🍷 Oxygen

Oxygen is a gas in the air that matters to wine at every stage. In small doses it helps wine mature: it softens tannins, strengthens colour and develops aroma. But in large doses it spoils the wine, causing oxidation.

In winemaking oxygen is needed for fermentation: it helps the yeast at the very start. After that it is limited so that the wine does not lose freshness. For this, barrels are kept full, tanks are closed and sulphites are added to the wine. A cork lets in a tiny amount of air, which also affects how the wine develops in the bottle. Micro-oxygenation, supplying oxygen in very small amounts, is used to soften red wines.

Interestingly, once a bottle is opened, oxygen begins to work faster. That is why wine "breathes": within minutes the aroma opens. But if left for long, the wine oxidises. What matters is measure. Oxygen is tied to wine both in the course of fermentation and in its storage.