Wine closure options go far beyond just corks. Over the past few decades, glass closures, screw caps, and various forms of synthetic closures have made their way onto the market, giving the wine world’s most traditional wine seal a run for its money.
Despite the vast array of options, the most widely used closure remains natural cork. The reason? Tradition. “We use cork over anything else because our estate is all about history and tradition, and cork is traditional,” says Marc Gagnon, winemaker and co-founder of Napa Valley’s Gagnon-Kennedy Vineyards. Gagnon notes that although alternative closure companies sell people on oxygen permeation replication similar to that of corks, which he fully believes eliminates TCA contamination (a chemical compound that can manifest in cork and taint a wine to the point of being undrinkable), he still feels that synthetic closures don’t follow his brand’s image.
Cork’s pros are pretty obvious: history, sound, ritual, aesthetic, and aging capacity. However, the cons of TCA and other molds, as well as variability among permeability and porosity, have led many winemakers to pursue alternative routes. For Richard Bruno, winemaker and president at Vinum Cellars, the answer was found in Amorim corks, a company which treats real cork particles at the granular level, then emulsifies and binds them.
“I have always believed that a natural cork is the best way to age wines properly, but allowing up to a 5 percent failure due to TCA is insane,” he says. “Simply put, it’s bad business.” Bruno reveals that after five years of working with Amorim, Vinum has not once received negative feedback or refund requests. The con? Price. Bruno notes that each Amorim closure costs $1, though for the quality guarantee that it provides, it’s $1 well spent. In comparison, lower-grade corks run about 50 cents per closure, whereas higher-end corks cost around 75 cents.
Pedro Fernandes, general manager of Amorim Cork America, explains that cork manufacturing is one of the most sustainable long-term practices in the world of winemaking. “Every piece of the harvest cork ends up being used either in technical stoppers or in other cork applications, such as cork flooring or cork insulation,” he says, citing its zero-waste and high-quality nature as additional pros.
In California, Drake Whitcraft made the shift from cork closures to Diams back in 2017 after a bad bout with TCA during his 2014 vintage. “We went from having TCA issues to having leakage issues in 2016, so I switched to Diam in 2017 and have used that almost exclusively,” he says.
Diam closures are produced from pulverized natural cork pieces (so technically, they are natural cork). However, unlike standard corks, pieces destined for Diam closures undergo a crucial process of passing through CO2, which removes all forms of TCA. Whitcraft says this process is “similar to the way in which coffee is decaffeinated.” After this process, the pieces are then bound back together with lanolin and beeswax and reformed into a newly formed — and more reliable — cork.
Whitcraft says that the only argument he’s heard against using Diams is that they keep the wine “too fresh” due to a lack of oxidation in the aging process — a complaint that he deems “absurd.” Additionally, Whitcraft notes that using natural cork creates environmental pressure, as the trees themselves are very fragile, and the zones in which they can be cultivated are diminishing. “The area where you can successfully grow Quercus trees [cork trees] is shrinking due to climate change,” he explains. “Demand has led to improper forest management, harvesting the bark too early. This harms the tree and makes [lower-quality] corks, but when dollar signs are involved, no one really cares.” To top it all off, Whitcraft additionally notes that most of the higher-quality corks end up staying in Europe anyway, as in addition to proximity, cork producers’ longest-standing customers are based in Europe.
Dan Pannell, winemaker at Western Australia’s Picardy Wines, has other thoughts on Diams. “Diams seem to scalp the wine, meaning that flavor is decreased,” he says, finding that these closures, as with all synthetics, are not good for cellaring. “Cork is the only closure to use if you want oxidative aging, as the quality is very good now,” he says.
In the south of France, Olivier Coste uses a variety of closures at Domaine Montrose, including screw caps, Vinoloks (glass closures), natural corks, and synthetic corks. “We use natural corks for our high-end red wines and Vinolok glass closures for our high-end rosés,” says Coste, citing aging reasons for the former and “elegance and prestige” as the impetus for the latter.
Coste notes that for its range of export wines, including its Domaine Montrose rosé, Stelvin screw caps — in which screw pitches are hidden inside the capsules for a “classier look” — are the closure of choice. “Our wines are fresh and meant to be drunk young, so screw caps are better, more practical, and keep the wines fresh,” he explains. With regard to the glass Vinolok closures, he says the decision is simply aesthetic. He says they’re less practical and, at 12 to 18 cents, they’re also twice as expensive as the Stelvin screw caps.
Elsewhere in France, winemaker Gerard Bertrand is a big fan of Vinolok glass closures. Bertrand finds that the closures are easier and more fun to open than traditional cork closures. “This closure is ideal for wines that are not made to age long,” he says, noting that Vinoloks are reusable, as well as have the option to be personalized, which Bertrand does for his line of “Cotes des Roses” wines.
For Bertrand, material and seal-tight nature are Vinolok’s two main assets. “It provides a hermetic closure that does not interfere with the maturation and evolution of the wine in the bottle,” he says. However, for his estate-bottled and biodynamically farmed wines, Bertrand opts for natural cork closures. “The main [advantage] here is that corks have good elasticity and keep oxygen out,” he explains, noting that cork’s ability to let in just the right amount of air is key to aromatic development. Cork’s promotion of biodiversity and renewable energy makes the deal all the sweeter.
Based in California’s Santa Lucia Highlands, winemaker David Coventry at Talbott Vineyards is a big proponent of screw caps. “The screw cap maintains the wine’s vivacity of youth and best preserves my vision for [our] wines,” he explains. Coventry finds that, unlike the variability that comes with cork, screw caps provide a much more linear and uniform aging profile. Talbott ultimately made the decision to switch from corks to caps for all his wines in 2010. “The screw cap is the best closure [for my wines] and offers a consistency I can’t get with any other closure,” he says.
In Santa Rosa, Calif., Hardy Wallace — winemaker at Dirty & Rowdy Family Winery — uses NomaCorc Select Bio closures. It was one of the first boutique wineries to do so back in 2014. “We switched from traditional cork because we were flabbergasted by the industry-acceptable failure rate and wanted to find a better alternative that would still fit our ethos,” he says. Wallace notes that, although screw caps have been around since the mid-20th century, they are made from materials that require mining, which is not environmentally advantageous.
At the time that Wallace made the switch, amalgamated corks, like Diams, were mostly bound by polyurethane glue, which he did not want in contact with the wines. Although the binding has since changed to beeswax, Wallace has still heard of “off aromas” being found in wines bottled with them. “The SelectBio closures were a perfect fit — technically superior, plant-based, carbon-neutral (now carbon-negative), recyclable, etc,” he says, citing that his extensive research caused him to have very little pushback from colleagues and consumers.
Unlike other alternative closures, Wallace notes that NomaCorcs actually cost less than traditional corks — about one-fourth the price of the high-end corks that the winery was previously using. The con? Many recycling programs are not accepting these closures anymore. However, Wallace is working toward a solution. As of last summer, he has been working with Vinventions (NomaCorc’s parent company) to set up a closure recycling program similar to that of mailing back empty Nespresso capsules. As of 2016, Dirty & Rowdy moved all of its wines under NomaCorcs. 2020 will be its seventh vintage under these closures.
With wine closures, the major takeaway is that quality, consistency, and sustainability seem to reign supreme, though expert opinions on the pros and cons of each option remain varied. The universal common thread, however, is the undeniable importance of keeping wines fresh, preserved, and above all, delicious.