1. Groupement Interproducteurs Collioure-Banyuls, GICB, F-66650 Banyuls/MER in conjunction with the Comité Interprofessionnel des Vins Doux Naturels, CIVDN, F-66300 Tresserre at the Bordeaux Faculty of Enology, Seguin-Moreau SA (F-16103 Cognac) cooperage at the Bordeaux Faculty of Enology. INSA-Lyon, Organic Chemistry Laboratory, F-69621 Villeurbanne Cédexe, and Faculty of Enology, Bordeaux II University, 351, Cours de la Libération, F-33405 Talence Cédex