Oxygen affects wine components and refines them.
Louis Pasteur showed that despite all the precautions taken, wine gets many opportunities to absorb oxygen – even through the barrels' wood.
Oxygen is not the only one at play in barrel ageing.
Wood too is a maturation factor. It provides aromatic and flavouring substances, such as tannins, vanillin, etc.
Time standards vary with wine characteristics and vintages (grape harvests).
At Château Bizard, some vintages remain in barrels for 12 to 14 months (one-fourth being replaced each year).
The aroma spectrum is subtle. Oak woods are of various origins and on medium heat.
Ageing in barrels stabilises the wine colour, improves its roundness, and acts as antioxidants.
