The cork empire strikes back


The purest, most gut-wrenching conflicts involve only two opponents. Rarely do spectators remain unmoved in a fight between two. It is right against wrong. Good against evil. Ali v Foreman. Coke v Pepsi. Godzilla v Ultraman. Cork v screwcap.

For many years has this last battle raged, often inspiring a venom unparalleled within the wine industry. It surely seemed bonkers to those without. Even Godzilla and Ultraman might have paused to roll their super-powered eyes at such absurdity. Yet the cork and screwcap debate remained a surefire way to shatter the conviviality for which wine is so renowned.

In many ways it still can, but there now seems to be a growing weariness with the same old weather-beaten arguments. Furthermore, as I learned in a recent visit to the beating heart of global cork production in Portugal, the rhetoric appears to be changing.

Taint necessarily so

Amorim is the world’s largest producer of cork stoppers (disclosure: they hosted me on this visit, but the flights were paid for by The frankness and transparency they now display is not what the cork industry was historically famed for. But I found their current acknowledgement of the impact of TCA taint – and what they have done about it – refreshingly honest.

'Plastic stoppers don’t keep me awake at night', Carlos de Jesus, Amorim’s director of marketing and communication told me, 'but a bad cork does'. To combat such restiveness, Amorim has established a series of stringent preventive measures which have at their heart one honest admission: that while their target for taint is zero, this may be impossible to achieve.

This is heartening to hear, because it confronts the reality of an issue that was often avoided in the past. Estimations of cork taint still vary a great deal. Amorim analysed the taint rate of the 8,000 bottles tasted at the 2012 Concours Mondial de Bruxelles wine competition, using gas chromatography, and found it to be 0.88%. However, of the many thousands of cork-sealed wines tasted at the Decanter World Wine Awards this year, 7% were reported as corked by the judges.

Command and conquer

In their continual efforts to reduce taint, Amorim have quality-control measures in place throughout the production process. New cork-processing factories were built in 2000 and 2001. Here, the wood that can transmit TCA is outlawed. All pallets are stainless steel, and all flooring is concrete with efficient drainage channels. Redesigned machinery ensures that cork planks are steam washed. In-house laboratories analyse up to 700 samples a day to monitor TCA incidence. Chlorine, which puts the C in TCA, is now completely outlawed and peroxide is used for cleaning instead. 

Throughout the process, every cork is subject to multiple checks. Electronic eyes can automatically reject any corks with visible flaws, in a system reminiscent of the automated grape sorters used by high-end wineries. Afterwards, assembly lines of human checkers swoop on any remaining miscreants that snuck past the computers. (To see the whole process in action, you can watch this video.)

Despite the cork producer's best efforts, some TCA can still get through. However, the latest development from Amorim’s R&D department might promise to finally banish tainted corks. This new technology uses non-destructive means to analyse individual corks via gas chromatography. In practice, this means heating the finished cork to 160 ºC for 10 minutes. If TCA is present, it will be volatilised and identified, and the offending cork can then be rejected. Current prototypes exclude 100% of corks with TCA concentrations greater than 5 nanograms per litre, and 88% of those between 2 and 5 ng/l. 

The major drawback is the time involved. Currently, one machine running non-stop could process 1.5 million whole corks a year, which sounds impressive only until you learn that Amorim make 900 million annually. Nevertheless, they hope that this technology might have a significant role to play in the future battle against taint.

Phenolic functionality

Amorim's R&D department is concerned with more than TCA, however. Another significant area of research concerns the transfer of oxygen through bottle closures, aka OTR (oxygen transfer rate). Currently, they are investigating how the make-up of natural cork might influence a wine’s evolution.

The OTRs of cork and Saranex-lined screwcaps return similar results, yet screwcaps are more frequently accused of being reductive. With this in mind, the Amorim team are investigating the phenolic compounds that constitute 6% of a natural cork closure. These are the same compounds found in grapes and oak barrels, and are extractable into wine over time. The levels of extraction are thought to be so low as to not actively influence flavour, yet significant enough to provide a catalyst for oxidative reactions – meaning that reduction is kept at bay. The thinking goes that the cork’s reputation may be bolstered by emphasising the potential positive impact it can have on a wine in such ways.
A more tangible piece of Amorim’s R&D was announced to much fanfare earlier this year: their new Helix closure. Carlos de Jesus acknowledges that screwcap has one advantage over cork – the former does not require a tool to open it. The Helix is an agglomerate cork made from small granules moulded into a T-shape. It fits into a specially designed bottle with a thread in the neck that allows the cork to be unscrewed to remove it, and then re-screwed to reseal it. After many years of development, it is now being tested with 12 wineries around the world, and the first commercial sales are expected in 2014.

It is a product intended for early-drinking wines in the £5 to £10 bracket, and there have been over two years of trials testing its reliability and performance. Clearly, there is a great deal of drive and investment behind the product. Amorim were careful not to expressly position the Helix as a rival to screwcaps – but this is surely a share of the market they would be happy to poach.

Something that was repeatedly mentioned, however, was a de facto ‘premium image’ of cork. It was taken for granted that cork equates with quality, and ergo that screwcap equates with inferiority. There was palpable despair at certain producers opting for non-cork closures on their flagship wines; by contrast, the world’s most famous wines were repeatedly cited as unassailable proof of cork’s premium image. 

There may be some truth in this. But there is also danger in a default dismissal of screwcaps, and the consumers and producers who choose them. It risks returning the debate to the sort of polarised dogma that made it so combative. In the UK at least, it would be unsafe to presume that the Helix will instinctively appeal to consumers on premium grounds. Even if the reason behind the success of screwcaps has primarily been convenience, they are now entrenched in mainstream wine-drinking habits, especially in the £5 to £10 bracket. For example, it is now utterly de rigueur for New Zealand Sauvignon Blanc – one of the most popular premium wine styles ever – to be sealed with screwcap.

The positive outcome is the fact that the cork industry is being stimulated to produce a higher quality product. De Jesus admits there are still ‘cowboys’ in the business, but when the largest company leads the way in developing better practice to create more trustworthy results, the outlook for cork as a whole is improved.

Campaigns about environmental sustainability and saving endangered species have been sensibly sidelined. Cork’s natural benefits will always be a part of the story – but the main message centres on cork's quality credentials.

With developments such as the Helix, Amorim is taking the bout between cork and screwcap into round two. It will be interesting to see how the screwcap market responds. Perhaps by creating a product requiring a special tool to open it ... or perhaps not. 

Either way, the outcome remains wide open. A knockout blow does not look imminent. And as these two sworn foes continue to slug it out, they might just learn to live with one other.