A battle is on about the use of natural corks in wine. Wineries that are turning to synthetic stoppers say it is because a small percentage of the natural corks leak, crumble or leave wine with a musty taste. This is true, there is always that risk if the wine isn’t stored properly. The wineries that I have visited all do technical testing of corks but it is not a guarantee.
Some wineries are moving from corks to metal closures. The reason for this shift is that an increased amount of wine being contaminated by cork taint, leaving the wine tasting musty and dull. The culprit for this unpleasant phenomenon, which can spoil up to one in 10 bottles, is trichloroanisole (TCA), a compound formed when chlorine used for bleaching reacts with mould already growing in the cork. Humans are incredibly sensitive to the compound and can detect it even at weak dilutions of six parts per trillion. TCA can flourish in several areas of a bottling facility, such as drains and barrels, but corks pose the biggest problem. “AZo Journal of Materials Online”.
Many types of grape wines are bottled using a cork sealed with a metal cap. The metal cap traditionally used on the better wines is made primarily of lead. Any lead product used in connection with foods or consumable liquids should be examined carefully to evaluate the danger of lead contamination. An earlier report by PERRE and JAUL~S (1948) showed that lead caps on wine bottles lead to an increased level of lead in wine. Lead Caps on Wine Bottles and Their Potential Problems by C. M. Wai, C. R. Knowles, and J. F. Keely- Department of Chemistry, University of Idaho. Today led is forbidden in many countries and metal caps are usually made of aluminum.
Scientists have shown that the long-term use of plastic corks in wine bottles leads to organic chemicals leaking into the wine, causing potential health risks. A report by the Leatherhead Food Research Association, a centre funded by the food and drink industry, shows that plastic corks can taint wine, causing an “off-taste” if it is stored for more than 18 months.
Plastic corks are cheaper than top-grade natural corks. The Mediterranean Region is the largest supplier of cork oak and they will be economically affected by this change. It’s not so much about economics to the wine connoisseurs as it the tradition and ritual that is at stake. They say that most people wouldn’t even know the difference. Plastic stoppers may be more acceptable to wine lovers then metal caps. Most wine lovers are clearly enthralled with the tradition of opening a bottle of wine with a corkscrew, listening to the pop when pulling it out and sniffing the cork. The process of a sommelier opening the wine at the table and popping the bottle is not going to be easily given up. A lot has gone into the romanticism of this process-it goes hand and hand with drinking wine.
Is the glass closure the answer since it seems to allow some oxygen into the bottle and the loved process of opening the bottle at the table with pomp and circumstances isn’t threatened?
According to Alcoa’s Closure Systems International new glass and acrylic closures provide attractive alternatives to corks and synthetic stoppers.
The elegant new closure looks like a decorative decanter stopper, and it is recyclable. Made with flexible o-rings, the stopper provides a sterile seal, preventing contamination or oxidation. An aluminum overcap and traditional neck sleeve will ensure mechanical protection and tamper evidence. Whitehall Lane owner Thomas Leonardini says “The glass stopper makes perfect sense. It is attractive, functional and eliminates the problems associated with natural cork.”However, the greatest benefit is that the possibility of cork taint ruining the bottle aged with a Vino-Seal closure system is zero,” said Leonardini. “And, the bottle can also be safely aged standing up.” Vino-Seal is also easy to open – no corkscrew needed. There also comes a second advantage: It is resealable. The contents of already opened bottles can now be sealed easily over and over again. In addition, the decorative stopper appeals to the aesthetic demands of connoisseurs.
George M. Taber says “I am interested in the new glass closures, for a red wine to age properly I believe it needs to be exposed to minute levels of oxygen over a long period of time, and cork seems to be the only closure capable of achieving this. However, when a closure is invented that keeps my wine safe from oxidation, allows it to properly age and eliminates TCA contamination from cork I’ll gladly retire my corkscrew”. GM Taber’s book, “Cork or Not to Cork”.
We are finding many more wines being served with metal caps, but mainly for white wines that are drunk within the first 2 years. I have to admit, I’m not excited about this and don’t like being served a bottle of wine with a metal cap. I have less of a problem with a plastic or glass stopper. There are about 350 wineries in Europe now using the glass stopper. I have yet to be served wine in a restaurant with a glass stopper, but I’m sure it is only a matter of time.
We store wine for a long period of time, especially when buying futures. The incident of a wine having a cork is small, but it is not a happy occasion when this happens. Ultimately the glass stopper may be an elegant solution that preserves the long time traditions of the wine industry and wine storage. The jury seems to be still out on this issue and it will be interesting to see which one wins, the old or the new.