The somewhat unwieldy term oxygen management describes all measures that influence the extent to which the wine or even the must comes into contact with oxygen. This primarily concerns the various steps of winemaking, but for years now research projects have been looking at how a controlled supply of oxygen via the closure can also positively influence the development of the wine during bottle ripening. The Nomacorc company, manufacturer of plastic closures for wine bottles, is making great efforts in this direction.
The starting point for the research is wine faults that can be caused by too much or too little oxygen contact of the wine. Nomacorc outlines the problem on its website as follows: "Reduction as a result of insufficient oxygenation during winemaking and ageing leads to an increased presence of undesirable sulphur-based components that cause an odour reminiscent of rotten eggs. Certain grape varieties and winemaking styles are more susceptible to reduction than others, and closures that allow minimal amounts of oxygen to penetrate (e.g. screw caps) are thought to support the likelihood of this undesirable reaction occurring. Oxidation occurs when there is too much oxygen in the wine. It leads to changes in colour and aroma. In most cases, oxidation is due to the introduction of too much oxygen during winemaking. It often occurs when little care is taken when bottling. The cause is often closures such as natural corks, which can have leaks or an irregular structure." Nomacorc also refers to an investigation on the occasion of the "International Wine Challenge" 2008, where several thousand wines from all over the world were tasted and judged. There, six per cent of the wines had been identified as defective, with 29 per cent showing reductive and 19 per cent oxidative off-flavours.