Corks, screw caps, synthetics, glass tops — there are all sorts of ways to seal a bottle of wine (or whiskey). “Closures” or “stoppers” have come a long way in the past 20 years, but some people still think a screw cap or a rubber “cork” signals a low-quality wine.
Though it’s possible you’ll find a wine bottle featuring some sort of bizarre Samurai suit stopper, these are the primary closures you’re likely to find on store shelves:
Natural cork: This is the classic wine stopper bored directly out of the thick bark of the cork oak, harvested around the Mediterranean. There are a wide variety of grades and classifications. Colmated corks are natural corks coated and sealed with cork dust to appear more consistent.
Granulated cork: Also called agglomerated or microgranulated, this is a composite cork made from granules leftover during the natural cork-making process (similar to particle board or presswood). Granulated cork is generally a less expensive product and often used for wines not intended to age (i.e. Drink-Me-Now wine).
Technical cork: With technical cork, you’ve got a granulated cork segment capped by discs of natural cork. This is designed for wines to be consumed within two or three years of bottling. They are stronger and more stable than regular granulated cork, and aesthetically pleasing (looks like natural cork from up top). Champagne corks are an example of a technical cork.
Synthetic cork: Synthetic corks are made from a wide variety of plastics, rubber, and composites and designed to look and respond like natural cork. You still use a corkscrew on these closures.
Screw tops: These are also called Stelvin caps after the most prominently known and used brand of wine screw caps. Unlike, say, the plastic screw caps atop maple syrup bottles, these metal caps with plastic interiors provide a very tight seal over the whole mouth and neck of the bottle. They are significantly less expensive than natural and colmated cork.
Capsulated cork: Capsulated cork, also called T-cork, is made of any variation of natural cork or synthetic material topped with a wider attachment made of wood, glass, porcelain, or other material. These are often used to add cred to a craft whiskey or brew.
Until the 1980s, cork stoppered about 95 percent of all wine bottles, according to Carlos de Jesus, the marketing director of Amorim, a large cork producer in Portugal. The first modern-style screw caps appeared as early as the 1960s, but were of fairly low quality. By the 1980s, screw cap technology began to improve dramatically, and Swiss winemakers hopped on board.
“In the beginning, many noses were turned up towards screw caps,” says Ranit Librach, the U.S. promotions manager for New Zealand Winegrowers. The entire country launched an initiative in 2001 to convert all or most wines produced there to screw caps. “But today, top wineries around the world, with wines priced in the hundreds, are closing their wines with screw caps.”
Why the shift? There are a bunch of reasons, many of which relate to the state of wine in the 1990s. Three things were happening at the same time. First, “new” regions — like Australia, Washington, and Chile — were coming on line globally. These areas were often exporting mass market wines to gain a toehold and were willing to experiment with everything from the fermentation process to the packaging. Secondly, wine collecting, especially in high-end categories like the Bordeaux-style Italian Super Tuscans and Napa Valley Cabernet Sauvignon, was becoming a thing for Wall Street, Silicon Valley, and so on.
Last, but not least, the cork industry was going through a rough patch in terms of quality control. Every once in a while you’ll find a wine that’s off or downright bad. Oxidation, fungal contamination, and other factors will ruin a wine’s aromatics, leaving a moldy, wet newspaper smell or other unpleasant odors and tastes. These faults are commonly dubbed as “cork taint” (yeah, yeah, we know), the implication being that a poorly made cork is at the root of the problem. More recently, we found that wine flaws aren’t solely cork-related (they can happen even before the wine is put in the bottle). In the ‘90s though, the 400-year-old wine cork was the chief suspect, in part because of cleaning processes involving chlorine-based compounds during production.
“The cork industry was kind of calcified at the time the wine industry started growing rapidly,” says Washington-based winemaker Co Dinn. “As a winemaker, I appreciate the history, and what makes cork such a special thing. At the same time, I came into this at a low point of cork quality. In the ’90s, there were instances of people having to decant entire bottling runs because of systemic cork problems.”
While he was the winemaker for Hogue Cellars, the brand conducted a detailed, decade-long experiment comparing the ability of a variety of corks, synthetics, and Stelvins to preserve wine over time, and found the screw caps preferable. He continues using them for his own line of wines today.
Dinn discovered that one of the big culprits in wines losing character over time was the introduction of oxygen. “Even in a carbonated beer sealed with a crown cap, oxygen can go through the plastic under the cap and affect the beer, making it taste uninspired. With a Stelvin screw cap, we found there were very miniscule amounts of oxygen entering the wine. I just opened a 2004 Chardonnay and it was beautiful. Not oxidized, and still exhibiting tons of fruit.”
But a lot has changed in the past two decades for the cork industry, according to João Rui Ferreira, president of APCOR, the Portuguese Cork Association (cork products of all sorts is a €1 billion industry in Portugal). New quality control standards have been implemented, along with an emphasis on cork’s natural and sustainable character (cork trees can be harvested for their bark over and over again every nine or so years, and the trees actually absorb more CO2 from the atmosphere after a harvest).
“It’s important to understand just how much work has gone into improving the industry and the products it provides,” says Ferreira. “It’s of course the best option if you want to keep your wine in the bottle for years, decades, or even centuries. But we’ve also created a variety of different products from the byproducts of natural cork, and those provide high-performance options that are as affordable as other closures.”
Education has been a big push for APCOR and producers like Amorim, teaching winemakers and consumers alike that technological and quality control changes in the industry have significantly reduced the presence “bad” corks, and that the perception of cork’s influence on tainted wines was bigger than its actual influence. Amorim’s de Jesus says improvements in the industry have been so influential that today, while cork makes up about 70 percent of all wine closures, use and sales are on the rise. “The growth rate, in terms of sales, today outpaces the growth rate of other stoppers or of wine itself. Starting in 2010 people began to see that the ‘problem curve’ for cork was going down while the ‘problem curve’ for alternative stoppers was going up.”
And many winemakers continue to find cork to be the best overall performer. Maggie Kruse, the associate winemaker for Sonoma County’s Jordan Winery notes, “We’ve done experiments with screw caps, and we still believe that oak-aged wines benefit from cellar time in a bottle with a cork, and that they remain more complex and expressive than those with a screw cap.” For one thing, there is a certain amount of oxygen you do want interacting with the wine, to mellow it and help give it depth. “A high-quality cork allows the wines to breath and evolve,” says Kruse. “This evolution is very important to us.”
And winemakers continue to experiment. Protea, a South African wine label, has introduced a Rosé and a Chenin Blanc featuring a twist-open, T-shaped cork called a Helix (also from Amorim) that is meant to be easy to remove (and reseal) without a corkscrew. It also mimics the visceral pleasure of a Champagne cork, basically blending the best elements of several closures.
What about hard liquor? Do the closures make a difference to that $50 bottle of whiskey hand-distilled by a bearded Brooklynite? Not as much. Distilled spirits are significantly less impacted by exposure to oxygen, even after opening (think about how wine goes bad if you allow it to sit around for three days, though who would allow that to happen?).
“I work from a practical perspective,” says Jonathan Pogash, a bar consultant who goes by the handle The Cocktail Guru. “In general, screw caps are always the best behind a bar, from a purely practical angle.” They’re easier to open and close, which helps when you’re making scores or hundreds of drinks each night. Most bartenders we casually surveyed on Facebook tended to agree.
On the home bar though, the capsulated T-corks look way cooler. There is one caveat: Those swanky silver-covered stoppers given as gifts can oxidize and impact fortified wines and liqueurs like absinthe or Aperol. Use them for that two-day-old wine, or even better, preserve it longer with a Coravin.
In the end, whether you’re talking wine or spirits, these days you’re in pretty safe hands however your wine is sealed. Here’s a quick rundown of everything we’ve learned about natural corks and screw caps:
- Classic option, especially for age-worthy red wines
- Sustainable and zero waste: One cork tree can provide cork bark for a century or more, and even the dust is used for biofuel.
- Now recyclable (not just reusable), thanks to Cork ReHarvest and Recork (both have drop-off stations near you).
- The visual and aural cues of cork add to the perceived value of the wine (think about the pop of a Champagne cork).
- Remember to bring a corkscrew!
- Still a small risk of a stored wine going bad, or a cork drying out.
- More expensive for the winemaker, a cost that gets passed on to the consumer.
- Consistently protect the wine inside.
- Convenient; no corkscrew required.
- Recyclable in many states, even with the plastic inserts.
- Saves money both for the winemaker and consumer.
- Though recyclable, they do have to be manufactured and are not sustainable.
- There is less romance and charisma.
- Some winemakers find they under-perform compared with cork.
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