In the competition with alternative wine closures, natural cork's most formidable foe has always come from within: 2,4,6-trichloroanisole, better known as TCA, the chemical compound that is the main cause of cork taint.
Amorim, the Portugal-based company that makes more than 4 billion cork stoppers a year—more than a third of the total global market—says it has a solution that will relegate the musty, damp basement smell of cork-tainted wine to a bad memory.
It's a patented process called Non Detectable Technology, or NDTech, using cutting-edge gas chromatography chemical analysis on an industrial level to individually scan corks. Corks with more than 0.5 nanograms of TCA per liter are rejected from the supply chain.
TCA is a product of chemical interactions between plant phenols, chlorine and mold. Natural cork stoppers are the by far the most common culprit of "corked" or tainted wine, but TCA can also form in winery cellars, basically anywhere wood and chlorine-based cleaning supplies come into contact. Peroxide- or ozone-based cleaning routines are now standard at most wineries.
"NDTech is not a magic bullet. We don't believe in magic bullets. This is the culmination of several projects, many years of research, everything we've done since we decided to defeat TCA," Carlos de Jesus, market and communications director for Amorim, told Wine Spectator. "Some things worked, others didn't. NDTech comes after building on everything else that we've done." Amorim's NDTech is the product of $10.6 million in research and development and five years of collaboration with British experts in gas chromatography.
Their invention won top honors at the Vinitech-Sifel 2016 Innovation Awards in the Vine and Wine category in November at Vinitech Sifel, an international wine, tree, fruit and vegetable trade show in Bordeaux, and wine producers like Bodegas Hispano Suizas in Spain, several Bordeaux classified-growths and Domaine Laroche in Chablis have already committed to using NDTech corks, which will carry a premium.
"Cork is indispensable; it's the best stopper for fine wines. This technology gives us zero faults," said Domaine Laroche vineyard and wine director Gregory Viennois, who also explained that NDTech corks were coherent with their commitment to sustainability. "We will only be using NDTech corks for our single-vineyard selections, grand cru and premier cru wines."
"Our wines and our customers deserve it," said Pablo Ossorio, partner and technical director at Bodegas Hispano Suizas, who was pleased to forget "once and for all the unpleasant odors" that even high-quality corks sometimes deliver.
The NDTech detection threshold of 0.5 nanograms per liter is the equivalent of one drop of water in 800 Olympic swimming pools—a concentration 500 times smaller than the approximately 1 part per trillion that seems to be the minimum detectable volume of TCA for those most sensitive to it. "Producing billions of anything is difficult. It's complex, especially when it comes from nature," said de Jesus of Amorim's cork output. "[We are doing] quality control on a product in the billions, in parts per trillion."
While TCA is the most common source of flaws in natural cork, it's far from cork's only weakness, and not all winemakers consider a TCA-free cork superior to a screwcap. "We have been using screwcaps … since 2001, and it has been one of the best decisions we ever made," said Michael Brajkovich, winemaker at Kumeu River in New Zealand. "[TCA] is not the only source of cork taint. Tribromoanisole, guaiacol and geosmin also [cause] problematic aromas that can be derived from corks, and then there are the woodlike characters that are a distraction. Since the change to screwcaps we have totally eliminated any form of these closure taints, and the wines are much better for it." Brajkovich also said that natural cork is a significant cause of premature oxidation.
Alternative wine closures like screwcaps, not susceptible to TCA taint, have made huge gains in the wine market over the past two decades. Ten years ago, the Portuguese Cork Association had 500 members; today there are 267. "The industry paid the price by not reacting strongly enough [to cork taint]," said de Jesus. "Natural cork stoppers used to have [nearly] 100 percent of the market, but by the middle of the last decade, it dropped to 67 percent."
Domaine Laroche famously turned to screwcaps with their 2002 vintage (and will continue to use the twist-off closures for early-drinking wines not meant for aging). The movement toward alternatives did not go unnoticed in the cork world.
By then, the cork industry had already been working to address the TCA issue. Technology for testing cork for TCA existed, and 10 years later, Laroche was convinced to switch back to cork by some of the new detection and elimination technologies. Amorim was doing 16,000 gas-chromatography analyses per month, but the operation took 14 minutes. It wasn't yet possible on the scale and speed required. "It was a bridge too far," said de Jesus. Today NDTech can scan one cork every 20 seconds. Amorim produced 10 million NDTech corks last year and expects to supply 50 million this year.
NDTech, says de Jesus, is just one part of cork's comeback story. According to recent Nielsen statistics, for the top 100 premium wine brands over the past six years, sales of wines using cork stoppers has increased 42 percent versus a 13 percent increase for those bottled under alternative closures. And the median price for a cork-finished wine was 39 percent higher than the median price for wines using alternatives.
Since 2009, Portugal's cork sales have been growing at 2 percent annually, with exports valued at more than $1 billion. For de Jesus, viable TCA detection technology signals the dawn of a new age for natural cork. "Today I think we can talk about a cork renaissance."