Corks and closures: sealing the deal


Debates on wine closures can largely be the result of initial reactions to the appearance of innovations or a sentimental attachment to their fore-runner. Nevertheless, it’s interesting to consider the various merits of different closures and also their down sides.

Corks

Clearly, the traditional means of closure has been well represented for centuries. Portugal produces almost 50% of the world’s cork, much of which finds its way into the neck of wine bottles. Cork trees live for around 200 years and can be stripped about every 9 years. They are widely praised as being a positive crop with benefits for the surrounding environment and wildlife. Similarly, they are recognised as the most environmentally friendly method of closure, as cork itself is inherently sustainable and easily recyclable.

French growers started using corks at some point in the mid seventeenth century, replacing the previous reliance on oiled rags (amongst other wild and wacky methods) as stoppers. Corks provide the best means for ageing red wines with a limited oxygen transfer encouraging long-term changes in the wine. The use of corks by prestigious and long-standing names in the French wine industry has played into the perception of cork as the superior closure and the only means for sealing premium wine.

Corks are not without their problems, however. One of the most common complaints about wine is that it is ‘corked’. This occurs when natural cork develops high levels of a chemical called TCA. This chemical causes unpleasant changes in the wine which can vary in their intensity. You should note that wine is not corked if it has bits of cork in it! Rather, wine will smell somewhat fungal or foxy and the palate will be muted but bitter. This natural fault occurs in something like 5% of bottles and is an unavoidable result of using natural materials. Nevertheless, intrepid scientists are working on means of conditioning cork to contain less TCA and halt the production of it in later years. The only real way to avoid such corked wine is to use an alternative closure, as described below.

Synthetic Corks

These tend to be made from plastics and often appear on cheaper bottles ready to eschew a screw-cap but not willing to invest in cork as a more expensive option. Clearly these offer little in the way of ageing potential as they aren’t especially malleable and don’t allow for air transfer. This will be perfectly obvious to anyone who’s ever tried to force one back into a bottle once it’s been opened. As these don’t mould the way corks do, you may find a sharp knife called into action to help you whittle a narrower end to force into the neck (or brute force)!

Screw Caps/ Stelvin closures

Although these closures endured something of a tumultuous introduction, they’ve quietly become the standard for a whole slew of wines. Basically, anything designed to be drunk young is perfect for a screw-cap. Although they predominate atop whites, some red producers are using them to seal wines designed for immediate consumption.

There is debate as to their use in bottle-ageing. They can help some bottles lie for up to 10 years, after which the interior can become brittle and fail. They certainly keep out more oxygen than traditional corks and this can help preserve the integrity of the wine.

The problem can come with gift-giving – I personally don’t like to give screw cap bottles as presents to friends. It’s irrational and fairly silly but it remains a misgiving which affects my purchasing decisions. Perhaps it’s an air of tradition which comes with cork which I want to see repeated in gifts. Personally, I’m more than happy to buy screw caps for my own consumption or for serving at my house, it’s just a bizarre prejudice that stops me buying them as gifts. Clearly they’re the equal of corks, although the problem remains one of image,

Zorks/Crown-caps/Vino-seals/Other things I’ve heard of but never actually seen

Zorks are apparently and Australian invention which, according to the publicity, ‘seal like a screw-cap and pop like a cork’. I have never seen one and feel in no way qualified to comment on it as a result. I’m dubious whether I ever will, though. I’ll keep my eye out at the London Wine Fair this year.

Crown-caps bring the worlds of wine and beer a little closer together. Although they are used at certain stages of the sparkling wine-making process, they are generally removed before shipping. Some wine-makers are now shipping their produce with a variety of this crown-closure which allows it to be sold as is. From what I can gather, these appear to be something like the caps that appeared on large bottles of Grolsch for a while and also adorn Tuborg bottles. Imagine a cross between a pull tab (like on a soft drink can) and a traditional bottle-cap. They’re intended for low-end sparkling wines, ensuring a perfect seal cheaply whilst still giving the satisfaction of a pop.

Vino-seals are not a water-dwelling mammal with a penchant for distilled grape juice. They are in fact something more akin to a traditional bottle-stopper (as you might employ at home). They are seemingly made of glass, which makes for a high unit price and helps to explain their scarcity.

It’s interesting that so many of these alternate closure methods seem designed to imitate the cork in some way. They are all valid options with their own attributes yet the endurance of cork is a signal of its trusted reputation. Likewise, it can serve as a mark of quality to the consumer, a fact recognised by the Spanish government when they banned the use of alternatives closures in 11 of its appellations. Screw-tops, however, have a definite role to play in the wine world, both in terms of convenience and economy. When it comes to sealing the deal, I’ll take whatever works!