The barrel was invented by the Celts to transport liquids or solids. Celtic ancestors built the recipients of the barrels just cupping inside pieces of logs and putting a lid. Then they got a perfect seal playing with the shapes of the pieces (flukes) and employing gold as the only aids wicker or wood
Until 50 years ago to winemaking as varied species of acacia wood were used, beech, poplar, chestnut, cherry, oak, etc. However over time the wineries concluded that single chestnut barrels and oak were able to favorably modify the taste and odor characteristics of the various wines. At present, the oak is practically the only one used by the contribution of aromas and technical properties.
Of the more than 250 species of oaks, belonging to the family of Quercus, only three are important for making barrels: sessile oak (Quercus petrea or Quercus sessiliflora), common oak (Quercus robur and Quercus pedunculata) and American white oak (Quercus alba).
Depending on the type of wine to be obtained, a type of wood or a certain origin is chosen. There are no set rules and depends on each winery. Also the degree of heating or roasting of the barrels influences the aromas are transferred to the wine during aging.
American oak is the most used in Spain, but in recent years has increased the use of French oak and from other sources, such as Russia and Slovenia. The American oak is lower tannin content than the French, in turn brings more aromatic components.
In French oak wood splitting is essential in the sense of the fiber to be fully finished waterproof barrels. This causes a lot of wood waste. The yield is 20-25%. Instead sawn American oak may interchangeably, regardless of the direction of fibers, so that the wood yield is much higher (50%), which of course affects the price. This feature of American oak is due, among other reasons, to a greater porosity and a thicker wood grain.