New oak and old oak

A producer describing a wine as "20% new oak" is telling you about the aromatic contribution. The proportion of wine that spent time in a barrel of any age is a different and often more consequential number.

Barrels are expensive — a new French oak barrique is a significant capital cost per 300 bottles — so the new-oak proportion is also an economic statement.

Vanillin, oak lactones and toast-derived compounds are extracted rapidly in the first months of the first fill. By the second use the aromatic contribution is substantially reduced, and by the third or fourth it is small.

Wood tannin follows the same pattern, so new barrels contribute structure as well as aroma.

Oxygen ingress does not follow that pattern. It continues through the staves and around the bung for the life of the barrel, and it is what drives the tannin and colour polymerisation that barrel ageing is really for.

A barrel’s high surface-area-to-volume ratio also keeps the wine in closer contact with its lees than a large tank does, which contributes texture regardless of the wood’s age.

Barrel size interacts with all of this. A 225-litre barrique has far more wood contact per litre than a 500-litre puncheon or a 2,000-litre foudre, which is why large old oak is the traditional choice where a producer wants oxygen without flavour.

It corrects the assumption behind "I want an unoaked wine". Someone avoiding oak flavour is well served by a wine matured in old oak, and there is no way to tell from the word "oaked" alone.