Corcho versus tapón de rosca: el dilema medioambiental

Interesante artículo de Jancis Robinson en el Financial Times sobre el dilema corcho vs tapón de rosca desde el punto de vista medioambiental y la batalla mediática que se está librando entre productores de uno y otro método.

Aunque el dilema medioambiental me parece complicado de dilucidar (como ella misma reconoce en la última frase) me han parecido muy interesantes las cifras sobre la cantidad de vino que se embotella ya con tapón de rosca, que asciende al 30% de todo el vino producido. Los corchos sintéticos o plásticos apenas alcanzan el 5% y parece que están en retroceso.

A mí esta semana me han salido dos TCA, así que estoy en fase proclive al tapón de rosca. ;)

Os lo dejo aquí en inglés y con Google Translate no debería haber problema para traducir.

Which is the better stopper for wine bottles, cork or screwcap? The fierce debate on this topic that raged in wine circles earlier this century centred on which is better for the wine.

There have since been considerable developments in the quality of both corks and screwcaps. And now that many consumers and producers want what’s best for the planet, it has all become much more complicated. Especially as there is no truly impartial, complete comparison of corks’ and screwcaps’ eco-credentials to guide us.

Today as many as 5.9 billion aluminium screwcaps are sold each year, compared with 13.1 billion natural corks and a dwindling number of plastic corks (about a billion). Screwcaps became much more common from about 2000 when Australian and New Zealand producers opted almost unanimously for Stelvin, the dominant brand of screwcap that has since become a generic term. They were fed up with the poor-quality corks that were then being shipped to them from Portugal, home of the cork industry.

Too many of these corks were affected by the most common taint known as TCA, which can render wine undrinkable or, worse because non-obvious, strips wine of its fruit to a greater or lesser degree. Imperfect corks also have an annoying habit of allowing a harmful amount of oxygen into the wine. Screwcaps may not be beautiful but offer 100 per cent consistency — what producers put in the bottle will be what the consumer tastes. Nowadays producers can even match the screwcap’s oxygen transmission rate to the type of wine.

The Australian Wine Research Institute is respected worldwide and its detailed studies on the evils of natural cork had considerable influence so that some consumers and producers have embraced screwcaps, even for quite smart wine.

The word ‘natural’ has come to cork’s rescue in this era of eco-consciousness. Cork forests act as a significant carbon sink

Regions differ. Americans are generally wary of screwcaps, as are the Chinese. But screwcaps are widely accepted by many nations including Brits. All wine that arrives here in bulk (41 per cent of still wines) is screwcapped, because that’s what the UK’s bottling lines have been designed to apply. At the same time, many of those Brits who drink more expensive wine are well-versed in the arguments in favour of a closure more consistent than a cylinder of the bark of a cork oak.

But Broadland Drinks of Norfolk, one of Britain’s commercial bottlers, announced recently that for the first time in 15 years, it was reintroducing a bottling line designed for natural corks “to help premium retailers and brand owners to cut their carbon footprint”. 

The word “natural” has come to cork’s rescue in this era of eco-consciousness. As long ago as 2010 Prince Charles, as he then was, argued that cork forests played an important part in preserving biodiversity in Iberia. The argument didn’t make much headway then, with Decanter magazine claiming that “it demonstrates once again that the cork industry’s grasp on the realities of public relations is as shaky as ever”. But a more easily graspable point is that cork forests act as a significant carbon sink.

Ever since 2008, the dominant cork supplier Amorim has been commissioning studies to showcase cork’s sustainability attributes in comparison to those of screwcaps. The results have gradually made their way into professional wine consciousness. Screwcap production may use much less water than cork treatments, but the Amorim-sponsored studies suggest that natural corks are superior not just in terms of greenhouse gas emissions but also non-renewable energy consumption and other key parameters. Today, Amorim provides its customers with a comforting estimate of how much carbon is sequestered by the trees responsible for the corks they order.

Aluminium’s principal sustainability credential is that it is infinitely recyclable and most of it is (although recycling programmes vary enormously between countries and even between local authorities). Wine corks lose elasticity so they are not really suitable for reuse and in practice most just go to landfill. For effective recycling they need to be shipped back to Portugal, to be repurposed into other cork products such as insulation, flooring, tennis balls and aircraft components. This is an energy- and emission-intensive exercise that has not so far been included in lifecycle assessments.

Both the UK and Australia have recently drawn up stringent packaging regulations with sustainability in mind. Along with a host of plastics, wine corks are currently classified as non-recyclable in both sets of regulations. In the UK, this means that special fees may in future be imposed on the use of such a naughty material — although it seems crass to impose admirable standards of packaging without offering a workable recycling system.

For what it’s worth, I take my used corks to a branch of Nicolas wine merchants in London which says, rather vaguely, that it sends them to a recycling centre. Majestic in the UK collects corks and gives the mulched product to the Eden Project to add to its soils. Recorked UK also collects used corks that are repurposed for crafts and it also seems to offer them for reuse.

The Wine Society in the UK is about to launch a cork-recycling scheme whereby it will mulch corks returned to its Stevenage HQ or its delivery vans. Diam stoppers made of agglomerate cork particles are accepted. Plastic corks (which can look disconcertingly like some smooth natural corks but are even less elastic) are not. They will eventually be sent back to Portugal.

In Australia the APCO initiative is aiming to phase out packaging materials that are not reusable, recyclable or compostable by next year so there’s an urgent need to work out what to do with the relatively few corks there. Retailer Dan Murphy’s recently launched a scheme to collect them, send them to a factory where they are turned into cork mats for the wine store staff.

Interestingly, APCO has also identified the PVDC (polyvinylidene chloride) film commonly used today to line screwcaps as unacceptable after 2025. Australian wine producers are so wedded to their Stelvins that the hunt is on for a biodegradable alternative. (It may be worth noting that Australia is the world’s leading supplier of bauxite from which aluminium is extracted.)

Some wine producers may be embracing natural cork today for qualitative rather than sustainability reasons. Amorim, for example, now offers, at a price (several euros a pop), stoppers described as “the world’s first natural cork with a non-detectable TCA performance” with a usefully reliable oxygen transmission rate. This is obviously a considerable improvement on a cork failure rate put as high as 5-6 per cent by some in the early years of the century. I still come across “corked” bottles horribly affected by TCA but they tend to be wines bottled more than 10 years ago.

Like many, I am convinced that screwcaps are as good for wine as a perfect cork, but can’t work out which is better for the planet.