Spanish scientist discovers limits to barrel aging

In her doctoral dissertation, Spanish scientist Teresa Garde Cerdán discovered that after 12 months of aging in oak barrels, red wine actually begins to lose the aromas and other components that oak brings to wine.

In studies of various factors involved in oak aging of wines (the age of the wood, the length of time the wine is aged, and the grape variety of the wine, etc.), Ms. Garde sought to categorize the interaction between wine and oak. Single varietals and blended wines were used, together with oak barrels from France and America of various ages. She discovered that wine aged in barrels that had been used for more than 5 years contributed very little of the aromas and volatile compounds sought in oak aging. In fact, older barrels imparted relatively high concentrations of ethylphenoles, compounds which negatively affect the aroma of wines.

The conclusions of the research indicate that, in general, French oak brings more aromas and components to wine than American oak, that alcohol level has a greater effect than pH in the tendency of wine to absorb aromas (the higher the alcohol level, the greater absorption), and that, above all, oak aging should be limited to 10 to 12 months. Ms. Garde observed that, according the her investigations, "after 12 months, in terms of the aromas in wine, the wine ceased to progress, and the compounds that give aromas began to decrease."

In the Spanish context, this is significant. The times for the aging categories of wine is mandated by the Consejo Administrador (Advisory Counsel) of the various Denominaciones de Origen: Crianza generally requires a minimum of 6 months oak aging, Reserva has a one year minimum and Gran Reserva at least 18 months. Importantly, the production of Gran Reservas is limited to exceptional harvests. But the study lends credence to the argument (which is by no means settled) that Spanish wines of lesser aging provide greater value for the money.