Have you ever wondered about the difference between cork and screw closures used on wine bottles? Most of us have. Here's a great education by Monty & Sara Preiser, publishers of a great wine information publication about Sonoma County, The Preiser Key. Next time you're in Sonoma wine country be sure to pick up a copie. You can also check it out online at: www.preiser.com.
CORKS vs. SCREW TOPS: DOES THE DEBATE STILL HAVE LEGS?
As wine writers and educators, as well as publishers and vintners, we are constantly asked questions about varying aspects of the wine industry. Probably the most often asked question has to do with what we think about screw top closures on bottles of wine.
Like with so many other inquiries, a simple “yes’ or “no” answer would be misleading. No matter which one word answer we would give, an explanation would have to follow in order to be accurate. Obviously, then, there are pros and cons to both positions, and these are affected by a myriad of factors, desires, and situations. We will try to cover the most important information and beliefs below, and finish with our own conclusions drawn on experience, study, and common sense.
It has always struck us as odd that in discussions about this subject we have never heard anyone question whether or not a finished wine is SUPPOSED to age. The only reason corks were used as a bottle closure in the first place was that there were no other substances available that could do the job and be opened in a reasonably simple manner. And does one suppose that the first people to employ corks thought about the slow aging process that would ultimately change the wine’s characteristics? Quite doubtful. Therefore, one might credibly argue that the changes caused by aging are NOT the natural or desired results of a finished bottle of wine. It could well be that a screw top, which inhibits aging for some indefinite, but longish, period, is the way things ought to be and would have been used long ago if available.
So at this point before any debate over screw caps vs. cork closures goes too far afoot, it would seem that the answer as to which is desired depends in great part on the individual and how s/he prefers his or her wine. If s/he desires higher fruit and youth, the screw top would be the way to go on wines of all types. If s/he prefers the emergence and ultimate flavors of secondary characteristics, then slow oxygenation permitted through the living and always somewhat porous cork is the answer.
For those who are certain they prefer the fruit forward, young taste of a wine, regardless of the varietal, the debate over which is better - cork or screw top - is moot. It should make no difference to them, except perhaps for some academic purpose. The pragmatic argument continues, however, for those who are interested in consuming wines affected by the traditional aging process.
As we know, natural cork is (or was) a living substance. As such, many factors can play on its makeup. The one that is most devastating to the wine industry is tricholroanisole (TCA), which transfers unpleasant musty smells and taste from the cork to the wine, which is then itself highly affected by losing fruit and structure. When this happens, a wine is referred to as being “corked.” Depending on one’s susceptibility to, and experience with, this smell, as many as 1 out of every 12-15 wines can be ruined to one degree or another. Obviously, the economic effect on the wine industry, which must replace these bottles and obviously lose its product, is serious. Consumers also suffer if they cannot get a refund, something that is sometimes impossible for many reasons.
Should you be thinking about synthetic corks (usually made of plastic so there will be no TCA), the problem with them seems to be that they have not shown much, if any, ability to stop oxidization, and so their use needs to be limited to wines that will be enjoyed relatively quickly. If chosen, then, one should realize the shelf life of a wine will become diminished, and there will be little chance for beneficial aging. All in all there is considerable doubt as to the efficient use of synthetic corks as a viable closure (not to mention that they are extremely hard on good wine openers).
To the screw top, or, if you like, screw cap. There is no doubt that, as a pure seal, these are better than anything else. They also, for all intents and purposes, eliminate the problem of a corked bottle and early oxygenation. What they do not allow is the romance of opening the cork, something not to be underestimated. Screw caps are also associated with cheaper wines – conversely, expensive and high end wines are associated with a cork. What is not yet conclusively established is whether screw cap closures allow for long term (perhaps decades or even generations) of aging.
The best known brand of wine screw cap is Stelvin, now owned by Amcor. Like people referring to all tissues as Kleenex, this closure is so common that many refer to all screw tops as Stelvins or Stelvin closures, regardless of brand. What sets the Stelvin apart from its competitors (not many left) is an aesthetically pleasing long outside skirt that resembles the traditional foil capsule on a wine bottle. Also, Stelvin uses polyvinylidene chloride (PVDC) as a neutral liner on the inside wadding of the cap, which creates a better seal than other substances.
While boxed wines using bladders and other closures such as glass are now on the market place and showing promise, their evaluations are ripe for another story at another time. The discussion here is limited to the two most common closures that spark the greatest numbers of questions and debates.
So here is our conclusion, which we think is quite credible under all the circumstances:
Most white wines in the U.S. will be consumed within a couple of years and so screw caps are the way to go. It just makes sense not to worry about TCA. For big Chardonnays designed to age, however, we think a cork is better and that the wines actually do improve if they age under proper conditions. As for red wines, once again we think screw caps would be fine for any of them designed to be consumed within a couple of years. But for most Bordeaux varietals and Pinot Noirs of quality, again we prefer a cork so that these wines can age and gain in sophistication. We are among those who love the wondrous secondary characteristics such as forest floor, leather, and dirt that are exhibited by an older red.
And here is the real bottom line. The question of cork enclosures has been around for a long time now – easily 20 years or so. Tests performed by screw top manufacturers or wineries with inexpensive portfolios are suspect for obvious reasons. Only high end wineries that lose a great deal of money from corked wines have the impetus to actually find a reason to use the screw top. So one can expect they have tried to discover some proof that screw tops are at least as good for all wines.
In all these years, however, there is no persuasive study (that means zero) that concludes screw tops allow a wine to age well and obtain those luscious flavors and nuances preferred by so many of us. If such a finding existed, you can bet the house that you would have heard it trumpeted to the mountaintops by now. We predict, then, that corks will be around for a long time to not only add aging ability, but to help maintain that special feeling that naturally comes with the opening of that anticipated bottle.