Wine bottle overcapping wax: An aesthetic or functional element?

Archaeological findings indicate that waxes and resins have been used for millennia as sealants to preserve bottled wine. Their use is largely linked to the belief that they limit the exposure of wine to oxygen. However, despite this historical use, the exact role of waxes and resins in limiting oxygen transfer has rarely been studied and even less so considering their ability to serve as overcapping materials to protect food and beverages. Hence, the present work investigated the effect of the presence of waxes/resins as overcapping materials and their impact on oxygen transfer through bottles corked with cork-based stoppers over a 1-year period of storage. The results demonstrated that waxes and resins have oxygen barrier properties which differ according to their chemical composition. For their application as overcapping materials, whatever the type of stopper considered, if the stopper has a lower permeability to oxygen than the wax and a surface treatment that effectively limits the transfer at the glass/cork interface, the wax will play a more aesthetic than functional role.