Effect of size, seasoning and toasting in the volatile compounds in toasted oak wood and in a red wine treated with them

The increasing demand for wood for barrel-making in addition to the rapid extension of alternative aging system, have led to looking into the possibility of utilizing Spanish oak. Quercus pyrenaica is the species that predominates in Spain, and the chemical composition of its heartwood (ellagitannins, low molecular weight phenolic and volatile compounds) and its incidence in characteristics of wine are similar to that of other species that are of recognized oenological quality for barrel-making, showing only quantitative differences with respect to French (Quercus petraea) and American (Quercus alba) species. However, at present, the quantity of good quality wood that we can obtain from the Q. pyrenaica Spanish forest is limited. Hence, in the short term, and considering the high chemical oenological quality of Q. pyrenaica wood, we propose the utilizing of chips, segments, staves, and other oak alternatives for wine aging, which would be obtained from wooden remnants from barrel-making as well as from trees with small diameters or physical defects which would normally be inappropriate for cooperage. With regards to the latter idea, studies on special chip-making processes, and other oak wood pieces are being carried out, especially focused on reducing seasoning time, and to toasting optimization as a function of wood piece size, in addition to its behaviour when incorporated into the different alternative aging systems. We present in this study the effect of seasoning way (traditional or unconventional) on volatile composition of Q. pyrenaica chips and staves at three toasting levels (light, medium and heavy), and the evolution of the wood-released aromatic composition of a Spanish artificially aged wine, using these alternative products. The wines showed in general small differences in their oak-derived characteristics, which were more related to the wood piece size and the toasting intensity than to the seasoning way, and they could be linked with the concentrations of compounds as eugenol, furfural, and the cis and trans isomers of beta-methyl-gamma-octolactone.