Among the perennial questions about wine, one has been developing consistently over the last twenty years: to cork, or not to cork?
Corks have previously been the mainstay of wine closures. We wouldn’t recognize wine without them. We sniff them upon being presented with one by the waiter, like we know what we’re doing. We keep them to commemorate events, to remember the occasion upon which we drank that 1994 Bodegas Vega Sicilia Gran Reserva (I wish). And plus, they make that very satisfying pop when they’re open, a sound we associate with something good about to happen.
Sidenote: in true wine and champagne service, the cork should never make a sound when it exits the bottle. Even when opening a bottle of bubbly, a good server or sommelier will ease the cork out with just the slightest whisper. The French say that the cork should come out in such a way that it “sounds like the sigh of a contented woman.”
Anyway. Corks. We know them, we love them, they are perhaps the top thing we associate with wine.
As of the last two decades or so, more ways to seal up wine bottles have emerged, primarily the synthetic cork, and the screw top. And, with change, inevitably comes controversy. (Literally, entire books have been written on the topic of wine closures. It’s a very, um, exciting topic.)
The primary use of a wine closure, be it a cork or otherwise, is to protect the wine from oxygen. Oxygen is bad for wine - it’s what makes the wine end up tasting like vinegar when you leave it out too long.
But because everything in life is tinged with irony and paradox, oxygen can also be good for wine, but only in controlled amounts. Some in the wine trade argue that this is the reason natural corks are the best closure - the natural cork allows tiny amounts of oxygen to interact with the wine in the bottle, helping it to age and develop complexity.
But natural corks also suffer from two key flaws. First, they can fail in their job to protect the wine from oxygen, and in doing so, cause the wine to age abnormally or to oxidize. Second, and more concerning, is their ability to develop “cork taint,” or TCA (which stands for trichloroanisole). TCA is a bacteria that’s present in some corks, and it basically makes your wine smell moldy and gross, like wet cardboard. Up to 5% of the wines in the trade are lost to TCA - an incredible amount, when you think about it. No other industry would consistently allow for a 5% loss without raising a fit. But, such is the power of tradition.
Hence the development of new ways to seal wine. The synthetic cork is just a cork made from plastic. It’s mostly impermeable when initially applied, and used mostly for wines that will be consumed within a couple of months of purchase. They don’t hold up well in the long term, so you won’t want to age a wine with a synthetic cork. For the wines you buy at Costco, however, a synthetic cork will do you just fine.
Lastly, and of great kerfuffle, is the screw top. Screw tops were initially championed by wine producers in New Zealand. First and foremost, these producers were far away from the center of cork production, which is Portugal. Getting natural corks was expensive. Second, these producers were losing a ton of their product to cork taint, and started looking for better options. The screwtop has been their savior, in this regard. The tops are largely impermeable to air, and don’t taint the wine. Trials have shown that they preserve the fruit flavor in the wine longer than natural corks do (which is great for the fresh and fruity New Zealand wines). There remains debate over how well wines under screwcap age. However, advances in screw top construction that allow limited oxygen transfer are currently on the market, so we’ll probably start seeing how well they work fairly soon.
A common misconception is that screwtops denote lesser quality wines. This is not true. In fact, they have nothing to do with quality. Yes, the fancy Burgundies and the expensive Bordeaux will most likely always be sealed with natural cork - but that has more to do with the French being French and Europeans being traditionalists than does a statement about the wine.
I’ve had some great German Rieslings, fresh Australian Sauvignon Blancs, and lovely New Zealand Pinot Noirs - all sealed by a screw top. In fact, while I write this, I am currently sipping a Chenin Blanc from Savennières in the Loire Valley. It’s sealed with a screw top. And it’s fantastic.
Do yourself a favor and remove any stereotypes you may have about the screw top. It’s good wine. Drink it.
So, let me sum this up:
Natural corks: Traditional choice and most widely used. Good for aging. Watch out for cork taint and cork fail.
Synthetic corks: Made of plastic. Solid choice for wines you’ll drink within the year. Don’t age a wine with a synthetic cork.
Screw tops: No relation to quality of the wine. Keeps the wine fresh with potential for aging.