Few topics in the wine industry yield more strong opinions than that of cork vs. screw cap. Corks have been the mainstay of wine bottle enclosures for hundreds of years. And, until recently, have been the only realistic choice. The past ten years have seen the rapid development of synthetic closures and, more recently, screw caps to seal 750 mL bottles of wine.
These alternative closures are used because they are much cheaper than corks, which can run up to $0.75 each. That’s a lot when you consider most wines have only a few cents worth of processing treatments performed on them. Presently, synthetic corks can be colored and used also for marketing purposes (red corks for rosé wine with clear capsules, for example). But these wines were never considered “fine” wines. And we all know about screw caps’ relationship with jug wines.
But there is a problem with natural corks. In its initial processing, cork is treated with chlorine to sanitize it. Sometimes though, a particular mold not eliminated by the chlorine ingests it and produces a chemical called 2,4,6-Trichloroanisol, otherwise known as TCA. It is made in very small concentrations, in the part-per-trillion range, that’s picograms per gram. In contrast, most of the foods we eat have ingredients in the mg/gram to gram range. Unfortunately for humans, not only is this chemical malodorous, our noses are extremely sensitive to it. Its odor has been described as moldy newspapers or corky. More insidious however is what it does to wine below the detection threshold. It masks the pleasant fruit and floral characters of wine, rendering it bland. In this case, you don’t know if the wine is tainted with TCA or whether there never was any of those nice fruit / floral characters to begin with. Worse still, discriminating TCA in wine is generally difficult for those not closely involved in wine production. That doesn’t mean most people can’t detect it, only that TCA is revealed in a more general way, such as “There’s nothing special about this wine.”
Cork taint is present in about 4 to 10% of corks. That’s a lot. No other quality control parameter would be allowed to reach such levels. Alternative closures were thus sought, and screw caps were found to provide a proper seal without the possibility of TCA taint. For any other food item, such a subtle change in its packaging would barely go noticed. Not so with wine. Screw caps have such an intimate association with jug wines that its presence on a bottle is as conspicuous as a fly floating on top of your soup. Add to that the ceremonial manner with which a bottle of fine wine is presented and consumed, and you realize how much the absence of a cork (and especially the addition of a screw cap) diminishes the ritual.
And this is the heart of the matter. Traditionalists place as much importance in the ceremony as the wine itself. Is the experience of opening a nice bottle of wine as pleasant without showing off your skill with a corkscrew and hearing that “pop!”? Or is it a psychological phenomenon of the ritual that reassures you that the $25 bottle of wine with a cork is indeed better than a $7.99 screw-capped wine? Just how much is that “pop” worth? More contemporary wine drinkers, however, place more significance in knowing that the wine inside the bottle is closer to how the winemaker intended it to taste. Many would rather not have to deal with finding a cork screw and broken corks (or worse, a broken cork that fell inside the bottle). To them, that “pop” just isn’t worth that much.
It’s as simple as that. Really. But traditionalists have created some concerns over screw caps, with a technical angle to it. The biggest criticism is that screw caps don’t allow the wine to “breathe.” What is breathing and why is it important? Breathing is the consequence of cork being porous. This means that air can be transmitted inside the bottle and conversely, wine can potentially seep through a cork and leak outside the bottle. The slow ingress of oxygen is an important element in the aging of a tannic red wine. Oxygen is required in the chemical process that turns a powerfully tannic red wine into a more approachable wine with a rich mouthfeel. Chemically, tannins form chains with anthocyanins (the chemical responsible for the red color) and other kinds of tannins. With time these chains become longer and longer producing more rich, soft tannins. Too much time can render these chains too heavy to be dissolved in wine and as such they become insoluble and precipitate in the bottle. This is the red sediment you see on the side or bottom of a bottle as you pour the wine out, and the reason that old red wines are decanted before consumption. Incidentally, the practice of “decanting” a newer bottle of red wine is completely ceremonial and never required. The “breathing” of a red wine prior to consumption, if preferred at all, can be performed in many ways, such as simply uncorking the wine some time prior to consumption.
Realize however, that the explanation above is applicable to a relatively small percentage of red wines. Wines that are very dark and tannic. This is not most red wines. If a red wine is pleasant to drink now, it will not improve with age. Aging a red wine when it is not required will actually deteriorate it, rendering it dull, oxidized, and very light in color. And if the wine was bottled with spoilage bacteria in it then you run the risk of the wine developing vinegar. Furthermore, all white wines never benefit from aging (with the possible exception of sparkling wine). As an aside, Rappahannock Cellars makes red wines with a range of aging potentials – our Meritage is an example of a red wine that will soften and become more rich with age.
For those of you interested in knowing the story behind why the waiter presents you the cork after opening a bottle of wine at a restaurant, it has nothing to do with cork taint (all corks smell corky anyway). It is traditionally done to confirm the wine you ordered is indeed the wine that’s in the bottle. Some unscrupulous restaurants sell the authentic wine and then refill the bottle with something else. The cork that is used to re-seal the bottle won’t likely be an authentic cork with all the tell-tale clues that identify the cork as having been the original one used to seal the bottle (the vintage date and name of the winery). This is typically only done with very expensive bottles of wine. The fact this ritual is done with inexspensive bottles of wine confirms the ceremonial nature of wine presentation. By the way, don’t smell the cork! For extra fun, ask the waiter if he knows why he is presenting the cork to you.
The second objection to screw caps is the observation that some screw-capped wines have a “sulfurous” odor to them. This link is an example of how the pro-cork campaign describes this phenomenon. Unfortunately, the wording is leading and the article leaves out a few important details. Let me expand on this. The “sulphidisation” the author speaks of refers to the presence of hydrogen sulfide (H2S) in wine, not the sulfur dioxide (SO2) used to prevent oxidation and kill bacteria in wine. H2S is produced by yeast in the alcoholic fermentation. It happens in all wine fermentations, whether the winemaker is aware of it or not. Regrettably, it has an odor of rotten eggs. Winemakers get rid of this odor in two ways, either by trying to “blow it off” by literally splashing the wine around in a tank, or by precipitating it out of solution with a fining agent (or both). Splashing it around works in two ways, by volitilizing off the chemical and/or encouraging an oxidative environment in the wine. This second effect of splashing only diminishes the foul-smelling symptom of H2S, it doesn’t actually remove it from the wine. When the wine returns to a less oxidative (reduced) state, such as what will happen when a wine is left alone in a tank or bottled, the foul odor will return. This is one of the more pesky problems winemakers have to deal with. If a wine is bottled with H2S, then it can potentially rear its head if the wine returns to a more reductive state (this is why a H2S-ridden wine is sometimes erroneously described as “reductive”). This will happen in both corked and screw-capped bottles of wine. However, it will happen more with screw-capped wines because screw caps provide a better seal, excluding oxygen from entering the bottle. H2S has nothing to do with the properties of the screw cap, it is only a consequence of a reduced state of the wine. Screw caps will encourage a reductive state and corks will not. What the author of the article did not mention is the fact that a reductive environment preserves all the things we like in a wine, like those fresh, floral, and fruity characters. You’re probably now wondering why H2S isn’t simply removed from the wine before bottling. Bingo.
Let me show you a funny thing that happens when people get wrapped up in this debate. This link points to an article written in the UK Telegraph newspaper, dated January 17, 2007. Knowing nothing about this subject, you’d be tempted to believe that screw caps have an unacceptable rate of taint compared to natural cork. But had you read this article, written in the same publication, about the same event, but by a different author 4 months earlier, you’d know that the rate of taint in screw-capped wines is half that of corked wines. It seems there really are “lies, damned lies, and statistics” even in this debate. On the other side is this study, performed by a winery in Washington state. Like anything else, you learn a lot more when you compare apples to apples, are objective, and have no ax to grind.
Where does this author stand on the issue? From a technical point of view, all white and rosé wines should be bottled to maintain a reductive (w/o oxygen) environment. If a natural cork can do the job, great. But I wouldn’t mind seeing screw caps on those wines either. For age-able red wines, natural corks are best. For other red wines, the issue is more cloudy. Most of our red wines (especially when excluding our Meritage) are drunk soon after purchase, where any aging effects won’t be very noticeable, so screw caps or corks would be acceptable. However, we don’t make wines to satisfy ourselves. There is a balance between making and packaging wine to best represent it, and the wishes of our customers.
-Jason
