The most commonly used wood for barrel making comes from oak trees. Wooden liquor barrels are made up of oak due to expedience and porosity. The American white oak barrel is primarily used for aging because it adds great flavors to whiskey and wine.
Reusing a barrel leads to diminished flavors, which means winemakers must replace barrels after every three vintages to make sure the wine flavor stays consistent. After approximately three uses, the oak no longer imparts flavor and becomes neutral oak.