The perfect closure: getting closer

Wines & Vines, May, 2003 by Larry Walker

Very few wine issues have polarized the wine trade the way closures have in the past few years. Defenders of cork have sometimes become a bit emotional in defending the product against those offering synthetic closures or screwcaps. Last year, APCOR, the Portuguese Cork Association, began a 2.5 million euro program to fund research with the objective of eradicating TCA in natural cork wine closures.

(TCA or 2, 4, 6-trichloroanisole, is a naturally occurring, odorous but harmless compound that certain microorganisms produce in the presence of chlorine. This chemical has been known to be a spoilage compound in natural corks.)

As detailed in our Sept., 2002 cover story about the Portuguese cork industry, APCOR's research will cover five areas of critical interest to the wine trade, including investigating the lifecycle of natural cork stoppers, the stabilization period of raw natural cork and natural cork's contribution to the maturation of wine. On top of this, APCOR will also be conducting tests on new treatments and developments within the cork industry and new processes with the sole aim of eradicating TCA.

Francisco de Brito Evangelista, the director for APCOR's International Campaign for Cork, stated, "This initiative is a breakthrough for our industry. It demonstrates clearly, and for the first time, that we are dedicating the appropriate resources to finding a solution to TCA in natural cork stoppers--industry-wide."

In January, Amorim Cork America, a division of Grupo Amorim, the world's largest producer of natural cork closures, announced laboratory findings confirming a further 60% reduction in TCA levels in the company's natural cork closures. These results were validated over a two-year period since the inception of Amorim's gas chromatography/mass spectroscopy screening by ETS Laboratories in Napa.

According to an Amorim statement, the recent decrease in TCA is a direct result of a $6 million research and development department founded in 1999. Another key to the TCA reduction is a proprietary cleaning system called CONVEX (Continuous Volatile Extractor) in place at the company's processing plants in Ponte de Sor and Coruche, Portugal.

"As the industry leader, Amorim has been working very hard to achieve a consistent and sustainable reduction in TCA levels over the years," said Daryl Eklund, general manager of Amorim Cork America in a statement. "TCA in Amorim corks has always been low and, in most cases, absent. But since we've begun receiving corks from our state-of-the-art Ponte de Sor and Coruche plants, we've documented an additional drop in TCA levels. Obviously, we are very happy to see this reduction validated by ETS Laboratories, but we also know that even greater advances are required. Because of Amorim's commitment to R&D and our unique technological edge, I am confident we will see further reductions in the future."

On the other hand, New Zealand producers who are using screwtops for closures claim a global surge in demand. Auckland-based Kim Crawford Wines and Marlborough's Lawsons Dry Hills Wines have switched entirely to screwcaps for their 2002 wines, including export wines destined for the United Kingdom, United States and Australia. Lawsons is also using screwcaps for 100% of its deliveries to Ireland, Denmark, Belgium, Hong Kong and Singapore.

Forrest Estate Winery in Marlborough on New Zealand's South Island bottled 50% of this year's exports in screwcaps, including 100% of its deliveries to the U.S. and Australia. Forrest and Lawsons use exclusively screwcapped wines for the New Zealand domestic market.

All three producers maintain that screwtops help emphasize their wines' intensely fruity flavors by eliminating cork taint and minimizing oxidation. They also credit screwcaps with sealing-in consistency and with allowing slow, even aging of wine.

"We were always confident that screwcapped wine would be accepted by a large percentage of consumers," said Erica Crawford, executive director of Kim Crawford Wines. "Even so, we've been amazed by the popularity of the new closures in just about every market." Kim Crawford was the first New Zealand winery to release a screwcap wine in August, 2001.

According to Crawford, the winery has been particularly surprised by the success of screwcaps in the U.S. She believes the new packaging gives the winery an "extra edge" as innovators in the competitive U.S. market, where consumers seem to be more interested in the quality of the wine than in the ceremony and mystique traditionally associated with corks.

Just what percentage of wine is corked is at the heart of the debate. The number is commonly reported at between 2% and 5%. Last year, the Wine & Spirit Association (a UK group) reported the final results of a UK survey of nearly 14,000 bottles of wine. The survey was launched in 2001, using results from British supermarkets in an effort to determine what the percentage of corked wines really is. The idea was that whenever a retailer opened a bottle of wine to sample, it should be tasted for cork taint. In the end, 13,780 bottles were tested, with cork taint affecting just 0.7% of the bottles. More of the bottles (1%-plus) were affected by oxidation than cork taint.