Making Cork
The synthetic cork shown here is just coming off the extrusion line and has been sliced but not yet treated or marked.
Suppose you sat down at a table with two glasses of Sauvignon Blanc and, after carefully sampling both, you describe the one on the left as having chocolate and plum overtones but the second is dryer with an astringent nose.
We’re not talking about a really subtle difference that only an expert could pick up on either – we’re talking about an over-the-head thumping difference.
So far, there is nothing special about this experience. Anyone who compares different wines has this happen all the time.
How surprised would you be to find out the two wines are identical? Not only the same varietal, but the same vintage from the same winery, the same plot, the same batch, aged in the same way and produced by the same wine maker.
If I told you the only difference was that they used two different synthetic corks, albeit both corks were from the same manufacturer, you’d be forgiven for being skeptical. When I sat down and tried those two glasses of wine and I was told that answer I was incredulous. So the people providing the test tried it again with a different wine, but this time I tasted three different glasses of red.
Obviously, my information must be wrong or incomplete. Everything couldn’t be identical else the wines wouldn’t be that different but I, along with seven others, most of whom are wine reviewers, were astonished when told the only difference was the variety of synthetic cork in the bottles.
All the corks are made by North Carolina-based Nomacorc and the differences in the corks are deliberate, a creation of years of careful testing and manufacturing decisions.
Nomacorc closures consist of a slick, polyethylene skin with a core of softer foam consisting of 60% air, but it is through (literally) the foam core that Nomacorc has perfected the manufacturing process to assist the wine maker produce the wine they really want.
The wines we tasted were identical except that each bottle was closed with a different Nomacorc from their 'Select' series. There are four different numbered models in the 'Select' series and each number represents a core that allows a different oxygen transfer rate (OTR).
Nomacorc’s VP of Global Marketing & Innovation is Malcolm Thompson. A chemical engineer by training, Thompson says, “We feel we’re the only [closure] company in the world that can do that, manage the OTR.”
Consider natural cork, taken from the bark of the cork oak tree. Beautiful as it is, natural cork does not have a consistent density and the rate of oxygen penetration of cork can vary enormously.
It is estimated that about 3% of all wine sealed with cork suffers from cork taint, which means that every year, approximately 360 million bottles of wine are thrown away. That waste results in considerable financial damage to every part of the industry from the wine maker right through to the final retailer. Too many tainted bottles can ruin a company’s reputation.
Notes Thompson, “Whenever there is a fault in wine the first place anyone looks is the closure.”
Aside from gross failure of that 3% of cork the more subtle issue is what did the wine maker intend when they bottled the final product? Considering the care paid to the fruit in the field, the processing, aging, and subtleties that make up any winemaker’s style it is ironic that the rate at which oxygen reaches the bottled wine –and which will have an enormous impact on the taste of what is finally poured– is almost random.
A red that ages in a cellar for five years versus a white that is meant to be consumed within a year need differing levels of oxygen exposure. Throw in a random number for oxygen exposure and the white could receive far too little or the red far too much, spoiling one or both.
As Nomacorc’s CEO, Lars von Kantzow, puts it, “Wine is one of the few consumer products where the consumer can’t be sure what they’ll get when they open a bottle.”
One criticism of synthetic corks made during the 1990s was that they cut off all oxygen to the wine, but wine makers have long known natural cork didn’t stop all OTR and tried to incorporate that into their wine making process.
Nomacorc has moved far beyond a cork with no oxygen ingress to a precisely modulated rate of oxygen transfer. The process is so carefully controlled that a wine maker can now order closures that will provide the OTR they believe will make the best wine.
For wine makers who aren’t sure what that rate is, the company has developed software, known as Noma Selector, to aid them based on the varietal, the region, the winemaking style, duration of storage and desired shelf life.
There are other kinds of synthetic closures available, from hard plastic which is oxygen impermeable along with screw caps, but Nomacorc’s founder and current team believes the process had to reflect what winemakers need. Nomacorc’s Director of Global Marketing, Jeff Slater says, “The twenty-first century technology gives you a control factor that is missing in natural cork.”
Natural cork still plugs the neck of most wine in the world, being placed in 64% of all bottles. Screw caps seal another 17%, which is followed by 13% for Nomacorc, now the world’s largest manufacturer of synthetic cork. Other synthetic cork manufacturers, including Tapi and NuKorc only account for 6% of the world market; although different manufacturers can be very strong regionally. NuKorc, for example is an Australian company, a market Nomacorc has not penetrated.
That is not the case in other winemaking strongholds – Nomacorc now claims 40% share of the U.S. wine market, 25% in Germany and one bottle in five in France.
Based on sales by volume Nomacorc says 30 of the world’s 40 biggest wineries use their closures for at least some of their product. ■