Influence of toasting treatment on permeability of six wood species for enological use

The major physical properties and permeability of six wood species, namely, Castanea sativa, Prunus avium, Robinia pseudoacacia, Fraxinus excelsior, Quercus alba, and Quercus petraea, have been investigated from the enological point of view. With permeability studies in focus, impregnation and evaporation losses were assessed by means of a hydroalcoholic solution similar to wine. Both native and toasted woods were tested, as toasting is a common pretreatment for barrels destined to be used in wine aging. Evaporation losses of all species, with and without treatment, follow a positively sloped linear model with R-2 adjusted >= 90%, whereas losses by impregnation followed an asymptotic model with R-2 values >= 80%. The effects of toasting are species specific. It was observed that the impregnation and evaporation losses decrease significantly in the species C. sativa, R. pseudoacacia, Q. alba, and P. avium. It is remarkable that toasted F. excelsior has total losses much higher than the other woods tested; thus, toasting of this type of wood is not recommendable for manufacturing wood staves for winemaking.