Hidden Messages in a Bottle

Most of us have discussed endlessly the issue of cork versus screw cap and other closures. What does cork give that screw cap doesn’t? How to avoid cork taint? How to avoid reduction when choosing the screw cap closure? The story is endless and many producers decided to adopt to change and put all their wines under screw cap whilst others have remained faithful to cork.

Last week at the London International Wine Fair, I attended a seminar on the use of oxygen in wine. This was a very technical seminar with most of the panel being oenologists, yet it took a different perspective towards oxygen in wine and hence ultimately touched on the closure issue. The main debate was how to manage oxygen in wine since ultimately this phenomenon is needed to produce wines and to age them well. One of the speakers, Stephane Vidal, a post bottling oenology specialist described the use of oxygen in wine on three different levels:


1. Macro Oxygenation – the use of oxygen needed for the yeast to kick off fermentation and to keep the yeast population at an optimum level.

2. Micro Oxygenation – this is the exposure of wine to limited quantities of oxygen which can happen either through barrel maturation or through the process of micro oxygenation developed by Patrick DuCournau in 1991. This method is used widely in Bordeaux and consists mainly in the polymerization of tannin into larger molecules, which are then perceived softer on the palate.

3. Nano Oxygenation – this is the oxygen needed for wine to be stored and aged well. Around 1/2mg per year is the ideal amount of oxygen intake to mature wine at its best.


As wine undergoes the various stages of production, less and less oxygen intake is needed by the wine to maintain a balance between the proper use of oxygen and oxygenation which can create faults in wine. So is the oxygen intake from cork closure important for wine? Can the head space used in screw cap closure introduce wine to more oxygen than needed? How does the quality of the cork influence oxygen intake?

Another important and interesting point raised during the presentation by Clemancy Yates, another oenologist, was the issue of bottling. After conducting her studies on bottling lines she concluded that fast paced lines used for the production of bulk wines introduce the wines to much less oxygen intake than slow paced bottling lines used for higher quality and less quantity wines. In her opinion, the advances being made on controlling oxygen intake at the various levels of wine production can lead to wine labels to include a best by date like all products found on supermarket shelves.

Oxygen transmission rate, optical technology, jet systems are all an innovative options given to the winemaker to take control of this phenomenon. Together with closure debates oxygen management is now one of the hottest topics in the wine industry. Poor oxygen management can lead to wine faults; too little oxygen can lead to reduction, it’s up to the puppeteer to manage the best show.

Oxygen & wine: research gets specific about oxygen, closures, bottling and aging.(COVER STORY): An article from: Wines & Vines