Winemakers have been using oak for centuries to enhance the flavors of both red and white wines.
The American Oak Barrel and the French Oak Barrel are the most popular. The wine maker can also decide on the level of toasting for the barrel itself – high, medium and low – that is desired to enhance the flavor. And, the wine can be a mixture of toasting – one part in a high toast barrel and the other in a medium toast barrel.
Read more about this aspect of wine making.