Food Packaging: Can quality control save cork closures?

Winemakers continue to address closure options.

Cork producers are addressing quality issues that have opened the door to alternative closures in wine packaging. (Source: Amorim Cork America.)

Coffee manufacturers and other beverage processors have contended with off tastes that result when chlorophenols and mold combine as TCA, but the phenomenon is especially troubling in wine.

Shorthand for 2, 4, 6-Tricholoroanisole, TCA creates a wet-cardboard odor in corked wine. An estimated 1 to 2 percent of all wine is affected by TCA-created cork taint, and that has led to growing use of alternative closures. About 8 percent of wines worldwide now use synthetic stoppers and screw caps, and U.S. wineries are in the vanguard of change.

“Cork taint got everyone’s attention, but the significant increases in the price of natural cork also have made winemakers more receptive to alternatives,” says Justin Davis, sales manager for Cork Supply USA, Benecia, Calif. The firm sells 250 million natural corks to vintners each year. It also handles sells Nomacorc synthetic corks, which have had a 10-fold sales increase in recent years. Kendall Jackson is expanding its use of the coextruded polyolefin foam product this fall.

Synthetic corks run on the same bottling lines as natural corks. The same can’t be said of metal caps, which require different equipment and bottles. PlumpJack Winery, an Oakville, Calif., vintner who’s made a big noise with a test of screw caps, leased the necessary machinery to apply Stelvin closures from Pechiney Cork & Seal Inc. Even so, “we spent over $100,000 to design the bottle and purchase 8,000 empty cases, and that’s a big expenditure for a small winery,” notes General Manager John Conover.

PlumpJack has put its Reserve Cabernet Sauvignon in screw caps the last three years. At $155 a bottle, it’s a mold-breaking precedent for metal closures and a PR watershed for Stelvin caps.

“We hope cork producers will eradicate TCA, but cork is the last remaining Old World technology in winemaking,” Conover says. “What other food product requires a special tool to open the package?”

Image sells wine, though, and Sutter Home Winery reversed course a few years ago when research indicated a return to cork would move more product than screw caps, according to Jack Squires, vice president of Amorim Cork America. Besides a multi-million dollar program to alter in-house processing procedures to address quality concerns, Amorim participated in development of a cork suppliers’ testing protocol for TCA. A solid phase micro extraction methodology using gas chromatography and mass spectroscopy was developed to detect TCA levels down to one part per trillion, well below the 6 ppt threshold that a trained oenologist can detect.

“We’ve seen significant reductions in TCA,” says Squires. “The problem isn’t solved, but we’re getting there.” And experimentation will lay bare the limitations of alternative closures. Squires cites the case of metal-cap compression at one winery when three pallets were stacked, resulting in seal failures on the bottom tier.

While Squires advises consumers to “stop being a cork dork and start enjoying the wine,” winemakers will continue to assess their closure options, in terms of quality perception and quality performance.

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Kevin Higgins was Senior Editor for FE.