Capping the cork

A natural stopper shortage has wineries
exploring alternatives to an industry tradition
Wednesday, August 20, 2003 | 12:00 a.m. CDT; updated 3:37 p.m. CDT, Saturday, July 19, 2008

It’s New Year’s Eve, 11:59 p.m. Guests are dressed to the nines and the party is in full swing. Beautiful wine glasses are passed out as midnight nears, but on this night there won’t be the customary pop of the cork. Instead there is a clink as the screw cap hits the floor.

While champagne is still bottled with traditional corks, the reality of this scene might not be far in the future. In the midst of a cork shortage, wineries are being forced to examine new alternatives to the customary cork wine stopper, such as plastic corks and screw caps. These are receiving mixed reviews from those in the wine community. While many experts say the alternatives do not hurt the quality of the wine, they can be damaging to a wine’s image.

The shortage in cork is a simple matter of supply and demand. The cork used for wine bottles comes from the bark of the Quercus suber tree in regions of the Mediterranean. The trees can only be harvested once a decade, and cork suitable for wine corks comes from the third harvest, about 50 years after the tree is planted.

The United States is lagging behind Australian and European bottlers in the transition away from cork. Here, traditional corks are still in the majority. The New York Times reported in May that American wineries use less than 10 million screw caps a year, while Switzerland, which has been using them for more than a decade, uses more than 70 million.

“There’s a lot of evidence that the screw cap is the best closure,” said Paul Vernon, owner of Top Ten Wines in Columbia.

“There’s a lot of evidence that the screw cap is the best closure,” said Paul Vernon, owner of Top Ten Wines in Columbia.

Nationally, many prestigious wineries are starting to bottle part, if not all, of their wines with screw caps and plastic corks. The Napa Wine Company in Oakville, Calif., recently converted one of its bottling lines to screw caps. Another California winery, Boony Doon Vineyard, bottled 80,000 cases of its wine in screw caps last year. This year, screw caps will be on 200,000 cases.

The lower supply of high quality cork is causing producers

to use a slightly lesser quality cork for the production of wine stoppers. Wines bottled with this lower quality cork are more susceptible to becoming “corked,” or tainted by a compound called trichloroanisole , which ruins the flavor of the wine. This is a major reason why wines are being bottled with alternative corks, but reluctance to change is slowing the transition.

“It’s really more of a tradition. Wine is expected to be corked,” said Ingolf Gruen, associate professor of food chemistry of the food science department at MU. “There is a reluctance by the wineries to start using them when they believe that they will bring the value of the wine down because of expectations.”

Les Bourgeois Winery in Rocheport is one winery that is moving slowly towards a transition to alternative corks.

“Most people are just waiting for market reactions to change,” said Les Bourgeois wine maker Cory Bomgaars.

Currently, Les Bourgeois is using both a traditional cork and what is commonly called a “one-plus-one” cork, a part processed and part natural cork. This type has natural cork on the top and bottom and pressed cork in the middle.

Bomgaars likes this type of cork better than a natural cork because it is a more consistent shape and size, and sits in the bottle more evenly. He also likes the part processed cork in that it cuts down on the percentage of wines ruined by being corked.

One to 5 percent of wines are destroyed by cork taint, Bomgaars said.

Cork taint happens when the cork molds, generating trichloroanisole . Corks that are treated with chlorine during manufacturing are especially susceptible, and improper storage is also a culprit leading to production of mold. Wine needs to be stored in a cool place, preferably a wine cellar, and is not supposed to be stored upright, Gruen said.

“When you have high humidity and a fairly warm temperature, the cork will start to dry out and the humidity from the outside basically starts seeping into the cork,” he said. After this happens, mold spores from the outside air will begin to grow in the cork, causing the taint.

The taint will cause a flavor change, Gruen said, and in extreme cases this flavor would be like what he describes as a “wet cardboard” or a “wet dog” flavor. In most cases there will only be a slight off taste, a slight shift in flavor that most people probably would not notice.

“A person who does not drink wine very often on a fairly regular basis, someone who might drink a glass of wine every other month or every half a year, probably wouldn’t even notice,” Gruen said.

Taste alone is the only way to tell if a bottle of wine has been tainted. It is a common practice to smell the cork to determine if the bottle has been corked. But Gruen said this technique isn’t very accurate.

“Don’t smell the cork. Smell the wine. The cork won’t tell you anything,” he said. “The cork will smell corky.”

Screw caps and plastic corks eliminate the chance of a wine becoming corked. But Bomgaars said Les Bourgeois probably won’t switch over to alternative corks until the trend picks up more.

“I would like to be able to use more screw caps in our system,” he said.

Besides slimming down the occurrences of tainted wine, the screw cap also preserves the flavor of the wine by cutting down on oxygen pickup. Wine can be stored better and longer with a screw cap, Bomgaars said.

Sarah Cyr, owner of the Wine Cellar and Bistro on Cherry Street, said the restaurant is beginning to carry quite a few varieties of wines with screw caps and plastic corks.

“The wines may lose some of the appeal, but we have a much better percentage of better quality wine,” she said. “Customers feel that they lose the traditional appeal of the cork, but understand that the quality of the wine is much more guaranteed.”

The quality of the wine is not tainted when alternative corks are used, only the image gets tainted. With time, and with higher consumer awareness and more tolerant perceptions, alternative corks might outnumber traditional.

“I believe, I predict, that we will see more and more of those in the future,” Gruen said.

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