New vs. old oak

The age of the oak barrel determines how much influence it has on the wine. A new oak barrel (1st use) releases abundant oak chemicals — tannins, lactones (coconut, vanilla), guaiacol (smoke) and eugenol (clove) — directly into the wine. Wines aged in 100 % new oak, such as grand cru Burgundy or Napa Cabernet, can have pronounced notes of vanilla, toast and spice that dominate the fruit. With each use the barrel's contribution diminishes as the soluble compounds are depleted. A barrel that has been used four times is called neutral and imparts almost no flavour compounds, but still allows controlled oxygen ingress that softens the wine. The winemaker selects the proportion of new oak (0–100 %) based on the desired style.