What are the aging classifications for Spanish wines?

To classify Spanish wines they are based on types of aging thus we have Crianza wines that need at least two years to be aged and at least six months in an oak barrels. Reservas wines are left in the cellar for a longer period, with at least three years, and they have one of these years in oak. The "Gran Reserva" wines are matured for an even longer period of time, including a minimum of five years aging, out of which there are two years of aging in the oak. They make a classification of the wines according to their quality and point out whether they are young or mature.