First a little on Oxidation
Oxidation is perhaps the simplest wine fault to diagnose and aside wine being served at the wrong temperature, is the most common consumer complaint.
The chemical changes that follow oxygen exposure are described below and take place within just 12 to 24 hours.
- The first chemical compound formed when oxygen reacts with the ethanol in a wine is acetaldehyde. At low levels this can make a wine taste ‘flat’ and vapid, and is responsible for the loss of a wines fresh fruity taste
- Further exposure to oxygen converts the acetaldehyde into Acetic Acid, the most common of all volatile acids and one of the two, common, sour tasting carbon acids which form the main constituent of vinegar
- The final chemical change takes place long after a wine should have been discarded and that is the reaction between oxygen and the phenolics. This causes the wine to change colour moving from amber to a brackish brown.
Still Wine Preservation
Still wines too oxidized (dull) to serve within just 8 hours without professional preservation
Wine begins to oxidize as soon as the cork is removed. Many red and some white wines benefit from a short period of breathing, but left in an open bottle rapidly begin to deteriorate as the air oxidizes the wine. Apple's are a great example, freshly cut white flesh quickly turns brown and starts to taste dull. Open wines too begin to brown, vibrant flavours & delicate aroma's dull until all that is left is a lifeless tannic or acidic liquid.
By removing the oxygen to a precisely controlled level Le Verre de Vin technology effectively preserves wine without any risk to it’s subtle structure.
Still wines preservation takes just 2 to 5 seconds (depending upon the amount of wine remaining) during which time a precisely controlled vacuum is created within the bottle. Precise control of the vacuum level is essential to ensure that the maximum period of preservation is achieved without any damage to the subtle structure of the wine.
TRUTH TIME: Hand operated vacuum pumps don't work, remove insufficient air and the wine continues to rapidly oxidize; remove just too much air and the negative pressure draws the delicate esters and phenols from the wines, detrimentally affecting the bouquet and ‘deadening’ the taste.
Link below show Le Verre de Vin system in action
The secret about Champagne and sparkling wines
'Research shows there are up to 30 times more flavour-enhancing chemicals in the bubbles than in the rest of the drink'.
Here is a link to the study reported in the journal Proceedings of the National Academy of Sciences (PNAS). http://news.bbc.co.uk/1/hi/sci/tech/8279073.stm
Champagne Preservation
Sparkling Wines too flat to serve within 2 hours without professional preservation
To successfully preserve opened bottles of sparkling wine and champagne, two key areas have to be addressed; loss of ‘sparkle’ and oxidation.
Preventing release of the naturally occurring CO2 is key to ensuring that the fizz stays locked in the wine and any issue of oxidation is eliminated.
Le Verre de Vin technology operates by introducing a precisely calibrated infusion of CO2 into the Champagne bottle, thereby creating a pressure equilibrium and preventing any escape of CO2 from the wine itself. A valved stopper is placed in the bottle and clipped in place (replicating the ‘wire around the original cork); the stopper retains the CO2 under pressure within the bottle and ‘locks in’ the natural fizz. The process ensures that bubble loss is prevented and maximum preservation is achieved
TRUTH TIME: Simply replacing the bottle’s original cork with a ‘clamp effect’ stopper will do little or nothing to slow bubble loss and the wine will continue to release it’s natural carbon dioxide (CO2) until a pressure equilibrium is achieved within the bottle (and oxidation begins).
Link below show Le Verre de Vin system in action
Do fortified wines need preserving?
The short answer is YES.
Due to spirit fortification these wines are able to stay open many times longer than table wines, but they still will oxidize and go dull & flat surprizingly quickly.
For example: Older vintage ports should be consumed in 24- 48 hours after opening, while some younger fortifieds will be ok for up to 28 days.
Oxidiation is still the enemy here and the same changes occur just over a longer period. By removing the oxygen to a precisely controlled level Le Verre de Vin technology effectively preserves wine without any risk to it’s subtle structure.
Preserving fortifieds using Le Verre de Vin still wine preservation will extend the open life of your fortifieds many time over, ensuring you are serving fortifieds as fresh as their winemaker intended.
WHAT ABOUT DELICATE WINES?
Comments from Roger Jones The Harrow Inn Little Bedwyn UK - Most restaurants should have a Le Verre de Vin system which either takes the air from still wines or puts a carbon dioxide blanket on champagne. This gives them a life of up to 21 days, long enough even for the smallest of restaurants. There is never a problem with champagne but I understand concerns regarding the extraction of flavours from a delicate aged red burgundy, although we have not [experienced this].
We are so confident in LVDV that we have four premium champagnes by the glass (Krug, Dom Pérignon, Gosset Grand Rosé and Gosset Grand Réserve) and in 12 months we have never had a problem. The confidence that LVDV gives to restaurateurs in opening better quality wines is huge. Our wines by the glass include Gosset Polish Hill Riesling up to Penfolds Grange 1997 (thanks to Tesco) at £30 a glass! We had Domaine Dujac 2001 Morey St Denis on by the glass for six months and never encountered a problem.
LVDV provides both consumer and the restaurateur numerous benefits, and allows fine wines to be provided at an affordable level. I was delighted to see and try a superb selection of wines by the glass earlier this week at The Square in London including an Egon Müller Riesling, Guidalberto (the second wine of Sassicaia) and two Tokays, one from the Barossa Valley and one from Hungary. All were in perfect condition and very well priced.
