Gonçalo M. Guedes, Ana Filipa L. O. M. Santos, Diogo P. Oliveira, C. Mariana Machado, Ana C. Lopes Cardoso, and António César S. Ferreira*
*Cork Supply Portugal, S.A. Rua Nova do Fial, 102, 4535-465 São Paio de Oleiros, Portugal (aferreira@corksupply.pt)

Managing oxygen exposure is a crucial and complex aspect of winemaking, affecting every stage from initial juice extraction to maturation. The amount of O² to which wine is exposed significantly influences its taste, aroma, and overall quality. In particular, white wines can suffer from premature oxidation during bottle aging, which deteriorates their sensory quality—a problem recognized since the 1990s, initially through changes in wine color. Research has since divided into two main paths: exploring how oxidation affects sensory perceptions and investigating the molecular mechanisms behind it.

The factors influencing oxidation in bottled wine include the wine’s composition and antioxidant content, the presence of transition metals like iron and copper, the bottling process, variability in bottle necks, treatments at the cork-glass interface, and the O² transmission rate (OTR) through the cork. These factors are influenced by storage conditions such as time, temperature, pH, and bottle orientation.

To tackle the variability in OTR of natural cork stoppers, a new process has been introduced into production lines. This process uses advanced imaging and deep learning to analyze the internal structure of corks and correlate it with their OTR, effectively distinguishing corks with high OTR from the standard range. This allows for real-time sorting of corks during manufacturing, ensuring that only those with suitable OTR values are used, thereby enhancing the consistency and quality of wine by minimizing undesirable oxidation effects. This method has been validated through established OTR measurement techniques (UVAMOX, Spain).

Funding Support: Cork Supply Portugal, S.A