Key facts
- A miniature bottle system was created to precisely measure oxygen transfer through cork stoppers.
- The experiment revealed four distinct phases of oxygen dynamics in wine bottles.
- Initially, oxygen diffused out of the cork itself into the wine.
- Phenolic compounds from the cork reacted with oxygen, consuming it.
- Later stages involved slow oxygen permeation from the external environment.
- The study aims to help determine optimal wine aging and drinking times.
A team of French scientists has developed an experimental rig to study the complex process of oxygen transfer through wine corks, revealing that corks play a more active role in wine aging than previously understood. Published in Science Advances, the study utilized a miniature bottle system to precisely measure oxygen kinetics without the complexities of a standard wine bottle.
The researchers identified four distinct phases of oxygen transfer. The first phase, lasting 15 days, involved equilibration between the wine and trapped gas. Surprisingly, during the first six months, the majority of oxygen entering the wine came from the cork itself, outgassing from its cellular structure. This phase showed that longer corks released more oxygen due to their higher internal oxygen content.
Around four months into the experiment, the cork began to chemically interact with the wine. Phenolic compounds from the cork leached into the wine, acting as chemical scavengers that reacted with the outgassed oxygen, effectively reducing the wine's oxygen content. This marked the point where the cork transitioned from a simple seal to an active ingredient.
After 15 months, the wine entered the fourth phase, characterized by a slow and steady permeation of oxygen from the external environment through the cork. The study noted that corks longer than 30 millimeters exhibited a very low rate of oxygen transfer during this final stage.
While the experiment did not involve tasting, the findings have generated interest from winemakers and cork manufacturers. The researchers hope that understanding the detailed oxygenation dynamics managed by different cork types and dimensions will eventually help determine the optimal time to drink a specific wine. Future work will focus on quantifying the interplay between the four discovered mechanisms and how cork variability affects these processes over time.