Why screwcaps should be preferred to cork stoppers for wine

various bottle shapes sealed by screwcaps

There are so many reasons for preferring screwcaps to any kind of cork (solid, compound or synthetic) as a closure system for wine bottles that I am simply amazed that more producers all over the world haven't yet made the change. The most adventurous, open-minded, or uncompromising on the quality of their wines have done so, to some extent. This is most evident in New World countries like Australia and New Zealand, where screwcaps are now in a clear majority. Their proportion is slowly growing in other countries, despite a rearguard lobbying action lead by the powerful cork producers which includes its fair share of red-herrings, half-truths and lies.

Many producers of quality wines who have not yet taken the leap are quietly experimenting in a hidden part of their cellars. Of the others, most are either ignorant or simply scared of public reaction in conservative-minded markets such as France and, it must be said, the USA. But if they all made the move at once then that would solve the latter problem instantly. I went so far, in my recent "6 wine wishes for the new year" (on January 10th) as to hope that screwcaps, or their equivalent, be made compulsory for wines in France. Obviously this will not happen and I am not seriously in favour of compelling anyone in such a manner.

So let's look at some of the issues here, point by point.

1). Wines no not age well through air coming in through the stopper. It is important to get rid of this commonly-held fallacy at the beginning. It was disproved way back in the 1960's by two eminent professors in Bordeaux, Paynaud and Ribereau-Gayon. And even if tiny quantities of oxygen can be beneficial to certain wines, a cork closure is not a reliable way of controlling this quantity, as solid cork, by definition, has variable porosity from one piece to another. Screwcaps, with the right underpad and closure system can do the job much better.

2). Variable oxidation from one bottle of wine to another within the same batch is the prime reason for consumers being disappointed with certain bottles of otherwise fine wines. Age 12 bottles of any wine for, say, ten years under cork (and often much less), then open all the bottles and you will see what I mean. Screwcaps obviate this problem (unless you bash them on the head).

3). Screwcaps cannot harbour the compound TCA, which is the prime cause of "corked" bottles of wine. Corks can and do, from time to time. So one can say goodbye to this problem, which affects an estimated 2% of wines sealed with corks, including the most expensive ones.

4). Screwcaps are easy to open, and just as easy to close, so less wine gets wasted and fewer people are frustrated and annoyed. You also do not have to carry corkscrews around with you any more. Bare hands will do fine.

5). Aluminuim used to make screwcaps is virtually 100% recyclable. It is also less bulky than cork to transport and so more ecological for transport. In any event, spending money and energy on producing and shipping bottles of wine that give no pleasure through cork-induced problems is a total waste of all kinds of energy and therefore fundamentally un-ecological. And before anyone statrs talking about cork being a totally "natural" product, maybe they should be reminded of the substances utilised in extracting, treating and preparing cork. Firstly there are all the fuels and other petrol-based products burned in getting into and out of the woods to strip the bark and carry the stuff around. During the production of bottle stoppers, chemical baths are used to condition the corks. Among the more popular are a chlorinated lime bath, followed by a neutralizing bath of oxalic acid, a hypochlorite bath which is then neutralized by sodium oxalate, and a peroxide bath neutralized with citric acid. One could also mention parraffin wax and other substances used to treat corks.

6). For those sensitive to sulphur dioxide, wines sealed by screwcaps require far less protection from premature oxidation by sulphur compounds. In fact adding no suphur almost becomes a more valid option, although I am not in favour of this as there is still a risk of the wine spoiling in various ways through latent bacteria, thermal variations, and over time.

7). Any wine spoilt by cork-induced problems is a rip-off for the consumer, a potential problem for the retailer and very bad for the image of the wine producer whose name is on the label. Therefore anything that removes this series of risks is a good thing.

8). Any minor technical problem that may be induced by incompetent use of screwcaps (slight reduction in some wines) is infinitely less noticeable than those induced by corks, and can anyway be solved, partially by using less sulphur, and partially by adjusting other procedures.

9). Screwcaps do not mask defects. It's a matter of "what you see is what you get". Hence competent winemakers, and good wines, stand out better from the rest under screwcaps.

my thanks to Luc Charlier and Vanya Cullen for a couple of the ideas in this article