The aging of wines is a process used to preserve wine but also to enhance its properties. It is a process of great interest, mainly because of the additional properties it adds to wines and because of its economic implications. Historically, barrels have been employed for centuries for preserving and aging wine due to their resistance and relative impermeability.

During the aging process, a series of chemical reactions take place influencing the composition and organoleptic profile of wine. At this point, oxidative aging in barrels is a fundamental step. Barrels are directly involved in the produced changes on wine’s composition due to the transference of oxygen and phenolic and aromatic compounds from wood to wine. This way, barrels act as an active vessel capable of releasing compounds that affect and improve wine’s characteristics.

Regarding, the importance of barrels during aging process, some attention must be given to the species most used in cooperage. These species are conventionally oak species, either French or American. However, other non-conventional species are currently being studied as possible wood sources for the production of wines, such as chestnut robinia or other oak species.

Wood barrel aging improves not only color and mouthfeel, but also increases aroma complexity due to the extraction of compounds present in the wood. These compounds include cellulose, hemicellulose, lignin, acids, sugars, terpenes, volatile phenols and lactones, being compounds of very different molecular weights. Aging in wooden barrels is a process used to stabilize the color and enrich the sensorial characteristics of wine. Therefore, an aging period in the wooden barrel is required to attain sensory fullness and high quality.

From a sensory point of view, the most important compounds are the following: compounds that provide coconut and woody aroma, smoky aroma, green wood, almond or spicy aromas. A study that observed the aging of the wine using different woods showed that the wood affects to 41 aromas of the wine, 11 of them depending solely on the type of wood used!