Barrels ad-hoc: Spanish oak wood classification by NIRs 

The wooden barrel is a key factor in enology, since wine chemical composition and sensory properties changes significantly in contact with the barrel^[1]. Today’s highly competitive market constantly demands new differentiated products and wineries search innovations continuously.

Wood selection is crucial: barrels stability to keep constant their contribution and the result on products, and additional and differentiated wood contributions to impact their new products. Oak wood selection has traditionally been carried out using parameters such as specie, location and grain, however, it goes one step further nowadays. Large cooperage work with non-destructive techniques that allow classifying oak wood quickly and easily according to their organoleptic contribution^[2].

CETEMAS studies Spanish origins oak (Q. petreae/robur) wood for cooperage. This is highly regarded by leading beverages manufacturer (wineries and whiskey distilleries). NIROB project led us to study the species, location and grain impact on the total phenol wood content, ellagitannin and volatile compounds profile, as well as the wood NIRs analysis implementation. After this study, it was concluded to modify the French grain classification scale for Spanish Quercus. Moreover, the first total phenol content prediction models were developed and applied on staves selection for wine barrels destined to a winery from PDO Vino de Cangas, with really good results.

During running NIRCHEM project, national and international oak are studied comparatively, improving the NIRs phenol content models and developing new ones to predict key compounds content for winemaker’s interest. The different origins oak chemical composition evolution is also studied depending on the seasoning and toasting.

Our goal is the wood knowledge before its selection, to choose the wood that best suits the characteristics sought by the wineries, offering a tool that allows this selection, enhancing and promoting, at the same time, the use of the country’s oak and its proper forest management.