Individual, species and geographic origin influence on cooperage oak extractible content (Quercus robur L. and Quercus petraea Liebl.)

Dry extract, ellagitanins, free ellagic acid, whisky-lactone, eugenol and vanillin have been quantified for a sample set of 61 pedunculate oaks (Quercus robur L.) and 72 sessile oaks (Quercus petraea Liebl.) originating from 6 different forests. Despite a very high interindividual variability, pedunculate oak shows higher level of dry extract, ellagitanins and free ellagic acid but lower level in volatil compounds compared to sessile oak. Inside a same species, differences between forests are less marked . Extractible compounds level is poorly correlated to the grain (ring width). Regarding cambial age, it might have its significanc e but lack of scientific data could not permit to conclude in that sense. Our results suggest that cooperage oak selection should be based on a species-provenance combination rather than on the grain or the provenance solely.