Scientific Study on Wine Preservation

We are drinking less wine but wine of better quality. This change in wine drinking habits led to the phenomenon of wine by the glass in restaurants and also at home. Bottles therefore remain open for longer, which raises the question of how to preserve the tasting qualities of wine. To meet this requirement, new wine preservation appliances have appeared on the market promising to preserve wine for long, very long periods (even permanently) and very often bearing no relation to scientific facts. EuroCave, an expert in wine preservation, appointed Institut Universitaire de la Vigne et du Vin (wine and vine university institute), of the University of Burgundy to carry out a study which would allow consumers to arm themselves with the relevant information when making a purchase.

Short synopsis of oenology

Wine’s greatest enemy, once the bottle has been opened, is oxygen, which causes the wine to oxidize and alters its original qualities.

An unopened bottle contains negligible amounts of dissolved oxygen per litre of wine. When the bottle is opened, this delicate balance is disturbed: ambient oxygen comes into contact with the wine and sets off the irreversible process of wine oxidation.

Initially, contact with air makes the wine develop in a positive way – leaving the confined space of the bottle allows the wine to develop and achieve a balance in terms of taste. Incidentally, it is something often suggested by sommeliers or done by wine enthusiasts when they decant the wine into a carafe.

Subsequently, the wine remaining in the open bottle increases its concentration in dissolved oxygen: 3, 4 sometimes even 9 mg/l, in this way changing the wine, by chemical reactions, causing the organoleptic qualities of the wine to deteriorate.

Solutions for slowing oxidation of wine exist

Faced with this natural process, solutions have been created to slow the development of wine and oxidation. It is not possible to preserve the wine permanently since once the bottle is open, oxygen has, to a greater or lesser degree, been in contact with the wine.

Two types of solution exist: either compressing the space at the top of the bottle by means of inert gas (argon and nitrogen), or establishing a vacuum in the space at the top (reduction in oxygen).

IT’S A FIRST IN THE SCIENTIFIC WORLD OF OENOLOGY. UP UNTIL NOW, NOBODY HAS ADDRESSED THIS ISSUE. I FOUND THE APPROACH INNOVATIVE AND INTERESTING.

Régis Gougeon, manager of the research team appointed by EuroCave

THE RESULTS OF THE STUDY

Scientific test phase

For the purposes of the study, researchers at Institut Universitaire de la Vigne et du Vin in Dijon, supervised by Régis Gougeon, worked for 8 months on experiments to determine the effectiveness of the process used by EuroCave’s Wine Art appliance, which preserves wine in open bottles. These experiments confirmed that the wine ageing process is slowed by controlled application of a vacuum in the space above the wine in the bottle, which reduces the oxidation process without changing the sensory profile of the wine, i.e. the flavours. « We also wanted to compare the effect of using different inert gases on the oxygen content that can be dissolved in the wine in the case of preserving the wine by compressing the space at the top of the bottle », explains Régis Gougeon. These experiments demonstrate the fact that nitrogen is as effective as argon and that the vacuum principle used by the Wine Art system allows the same results to be obtained without using inert gas.

Expert taster phase

Moreover, the effectiveness of the Wine Art system was confirmed by a panel of expert tasters who found no difference between bottles that had just been opened and identical bottles that had been opened, partially drunk and preserved by the Wine Art system for periods of up to 7 days. The panel of tasters also highlighted the fact that the Wine Art system, compared with preservation systems that use inert gas, is the system which most effectively retains the original tasting qualities of the wine.