The kinetics of oxygen ingress into bottles closed with natural cork stoppers was investigated by a nondestructive colorimetric measurement method using the oxidation of an indigo carmine solution. In order to encompass the natural variability of cork regarding its oxygen ingress into the bottle, 600 natural cork stoppers from different quality classes and produced from cork planks of different calipers were analyzed. The kinetics of oxygen transfer was similar in all cases and could be adjusted to logarithmic models. A significant variability was found for oxygen ingress into the bottles closed with natural cork stoppers: ingress at 12 months ranged from 0.3 to 4.8 mg; 21% of the stoppers reached the limit of oxygen quantification along the experiment. The results suggest that the variation of oxygen ingress is a consequence of the natural differing features in the cell dimensions and air volume within the stopper’s structure.
- ©2013 by the American Society for Enology and Viticulture