SUMMARYFrench scientists at the University of Burgundy published a study in Science Advances showing that corks regulate oxygen transfer in wine bottles rather than serving only as passive seals. Their mini-bottle experiment linked controlled oxygen ingress to wine aging, while too much oxygen can cause oxidation that makes wine stale, brown, and unpleasant.
Most people perceive a cork in a bottle of wine as a simple plug meant to keep the liquid in and the outside world out. In the recent study published in Science Advances, a team of French scientists demonstrated the cork is way more than that. By regulating the oxygen transfer into and out of the wine bottle, it works almost as another ingredient.
“Twenty years ago, our group focused on the oxidation and aging of wine and all its parameters,” Thomas Karbowiak said. “Oxygen diffusion through cork stoppers is one of these parameters.” Karbowiak is a chemist at the University of Burgundy, France, and the senior author of the study.
The mini-bottle experiment
Oxidation is one of the key drivers of wine aging. A slow, limited ingress of oxygen helps wine mature, smoothing out harsh tannins and bringing out an aromatic complexity. But when too much oxygen gets into the bottle too quickly, it can make the wine stale, brownish in color, and unpleasant to drink. That’s because it will also react with alcohol and phenols in the same process that makes a cut apple turn brown.