I’m a secret member of the ANC Anonymous. I go to weekly meetings of our Anti-Natural Cork group and stand up and say (depending on whether or not I’ve had a corked bottle of wine that week) “it’s been three/four/five days since I’ve been rude about cork closures.” Every time I have a corked bottle of wine I’m ready to launch into a diatribe about producers who think that bunging the bark of the cork oak into a wine bottle is the grown-up way to seal the container. I am advised by my wife (not always the most tolerant human being on the planet) that counting to ten is a good strategy. It doesn’t work when it comes to cork taint. The closure is the simple final stage of producing a bottle of wine: make the wrong choice and all the hard work (not to mention the consumer’s investment) has been a waste.

Corks were the best way of sealing a wine bottle in an era before space travel, the internet and flushing loos. They were so good for so long that no one seriously contemplated an alternative. However, they’re not perfect, and their defects are not as easily dismissed as the cork producers would have us believe.

Firstly, they are inconsistent. From the very same batch of corks, some will admit virtually no oxygen, while others are as porous as a sponge. This issue – known as random or sporadic oxidation – means that they fail in the one function for which they were originally intended – which is to keep the wine from spoiling through uncontrolled exposure to air. Secondly, they are prone to tainting the wine. Wine producers, conscious of the fact that corkiness is what has alerted retailers to cork’s shortcomings as a closure, have brought considerable pressure to bear on their suppliers. Despite this, contamination remains an issue. In fact, to take a slightly uncharitable view of the current situation – it is clear that only once alternative closures started to gain market share did the cork producers begin addressing the question of taint.

Finally, corks have a limited shelf life. We like to think of them as immortal – or at least as age-worthy as the wine they’re meant to protect. The truth is that, over time, they saturate with wine. Skilled sommeliers can ease an elderly cork from a bottle, and, armed with funnels, filters and prongs, they can pretty much open, decant and serve century old collectables. However, the fact remains that corks become less substantial and more like old Roquefort the longer they lie in contact with the wine.

For the better part of the past two decades we’ve known that screwcaps or stelvin do a much better job. They offer a choice of near perfect hermetic seals, as well as finely tweaked controlled oxidation. Originally they didn’t look pretty, but nowadays they come with long capsule-like sheaths so that the bottle looks as it did in the golden days of cork. True, winemakers have had to learn how to manage a closure that really does not allow the ingress of oxygen, and not all so far have succeeded. But this is a little like blaming a bottle manufacturer for what goes wrong with a wine that has been poorly prepared for the bottling line. The issues of reduction and bound sulphur – the preferred complaint of the cork lobby – are little more than a red herring: the vinous equivalent of blaming the car for the bad driver who crashed it. The very fact that the cork producers have leapt onto the reduction bandwagon is an indication of their desperation. If you can’t blame the equipment, fault the operator.

Of course this has become a multi-million rand game, with the cork companies investing heavily in wining, dining and schmaltzing wine hacks. Among my wine-writer colleagues there is actually one who is a paid spokesperson of the cork lobby, and several others who have “seen the light” (the way cork producers have stage-managed it), ever since accepting freebies to visit the groves of cork oaks in Portugal. It’s easy to tell who they are, by the way: they’re the ones who pooh-pooh the stats about cork-related wine defects, or blame reduction on screw-caps rather than on poor winemaking.

If the soap soft approach doesn’t work, the cork industry is ready to play hardball: when it emerged at the judges’ feedback session that there had been something of a cork-taint problem at this year’s Old Mutual Trophy Wine Show (of which I am chairman), a major cork producer threatened the show’s sponsor with legal action. Their letter of demand implied that since the discussion happened under its watch, the sponsor might be liable for any damage to the reputation of cork.

Sadly for the owners of cork oaks, the processors of corks, the hacks on the take and those nostalgic for the light popping sound of the old-fashioned way of opening a bottle, the evidence in favour of stelvin/screwcaps is now overwhelming. They don’t taint the wine, they don’t mismanage the rate of oxidation, they last at least as long as soggy old tree bark and they are far, far easier to open. They also lead to better-matured wines. A test conducted in Australia with wines which had been sealed on the same day, from the same tank, using both corks and screwcaps, and then left to mature for between seven and 16 years, showed that only two of the 32 pairs were better for having been aged under cork.

If you are going to be green about things (cork is apparently more carbon friendly), you presumably buy the whole anthropogenic global warming story, and have already given up your 4×4 for a Prius. If you’re worried about the habitat of the Iberian eagle and the Barbary deer, donate generously to the World Wildlife Fund. A good way to put money aside for this would be to take 5% of whatever you would have spent on cork-closed bottles. Even now, after years of promises and research by the manufacturers, that’s still the average rate of attrition attributable to cork closures. DM