Only a group of complex varieties have the gift of ageability (or bear specific qualities that help to age well). Tempranillo belongs to this select group, together with other minority varieties. Not all wines are good candidates for ageing. The wine to be aged need to bear certain components such as alcohol, tannins, acids, colour, etc. in the level and proper proportions. Those selected wines are such because they certainly have the necessary qualities to improve their organoleptic properties over time. During the time that the wine remains in wood, it experiments a quiet and continuous development. Yhe primary fruity flavours decrease and as the wine is aged, it builds up more complexity, mellowing and enhancing with different aromas and flavours. This evolution is due to the contact with the wood itself on the one hand, and on the other, to the gradual oxygenation of the wine. This conveys a remarkable transformation that is going to depend on factors like the time spent in the barrel, the type of barrel and the environmental conditions in the wine cellar, among others. As we know, Rioja wines are classified according to the ageing periods in cask and bottle, as Crianza, Reserva and Gran Reserva.