The number of uses of an oak barrel has an impact on the final taste of the wine. The newer the barrel, the more it will give the wine more flavour and tannin.

Less famous Bordeaux vineyards use barrels that have been used before and therefore the effect isn't the same as it is in the case of quality wines.

The aroma of the wine may be influenced by the method of matching the barrels and the origin of the oak tree, but also by the intensity of the charcoal and the thickness of the staves.

Oak is divided into two categories: American and European (that is, French, and, occasionally, Eastern European)

French oak has a fresh and delicious taste, and American oak is sweet and has an intense vanilla flavour. However, nowadays American oak is well smoked and as effective as French oak (and it is better than the French bad one) - although it tends to be more suitable for aromatic grapes from warmer areas.

Classic red wine of Spain, Rioja, is the best example of wine aged in American oak barrels (mostly borrowing the very distinctive smell of sweet vanilla). This wine is easily recognized due to the American oak flavour.