Since ancient times, a wide variety of woods from the tree species acacia, eucalyptus, chestnut, cherry, palm, pine and cedar have been used to make wine casks. Wooden barrels were hardly known in ancient Greece, but the Greek historian Herodotus (482-425 BC) reports of such barrels in the city of Babylon, which were made of palm wood. It is considered fairly certain that the Celts were already using wooden barrels for transport two to one millennium before the calendar and that the Romans adopted this skill from them. However, the most suitable wood for wine storage or barrique ageing is oak. It is one of the hardest woods, tough, very durable and still easy to work with. In addition, the nature of the ring-shaped pores prevents liquids from passing through the wood. This is ideal for the construction of all kinds of vessels, especially barrels.
Affinity between oak and wine
Last but not least, oak wood has a natural affinity with wine. In France, this was recognised early on and has been used for centuries for the barrique type of barrel created in Bordeaux. There are around 300 species of oak worldwide, but only three white oak species belonging to the taxonomic genus Quercus are used for wooden barrels. Two of them grow in Europe. This is the winter oak, holm oak or sessile oak (Quercus sessiliflora or petraea), and the summer oak or common oak (Quercus robur or pedunculata). The third is the American white oak (Quercus alba) with numerous species. As a rule, American oak produces more astringent and aromatic wines than European oak. For the sake of completeness, we should also mention the oak species Quercus suber, from whose bark corks are made.
Production of oak barrels
Wood from trees that are at least 80 to 100 years old is used for the oak barrels. After completion, they are subjected to toasting (barrel burning). A distinction is made between three groups of wood phenols that enter the wine during barrique ageing. The primary ones are leached out directly, the secondary ones are formed chemically and microbially from the wood phenols and thirdly, there are those that are formed by the degradation of the oak wood component lignin. The most important of these aromatic substances include eugenols, furfurals, lactones, tannins, terpenes and vanillins. Fine-grained woods release these substances slowly and in smaller quantities and coarse-grained ones quickly and in larger quantities. The grain size is expressed in French, for example, as "grain fin" for a fine-pored wood and "grain gros" for a coarse-pored wood.
Until the beginning of the 20th century, oak wood came mainly from Poland, Latvia and Estonia. Today, the wood comes mainly from France and North America. The American oaks of the species Quercus alba grow mainly in the dry forests of eastern North America. The most important production states are Arkansas,...
