Vive la Différence! Closure-based Trials Let Air Into the Debate Over Oxygen Impact

It’s was brilliant spring day in Napa Valley and people were strolling the sun-dappled lawns of the historic Charles Krug Winery. While the sunshine was a perk, the real draw that day was the inaugural Innovation + Quality conference—and the wealth of industry research on display.

In the exhibition hall housing a series of wine trials, a knot of people gathered around enologist Alan Kim, of Schug Carneros Estate, who was pouring samples of wines bottled with wine closures that let in different amounts of oxygen.

Kim was presenting six wines—half Sauvignon Blanc, half Pinot Noir, each trio TTD_Support1identical except for the wine closures. At his recommendation, tasters started with the closure with the least amount of oxygen and moved on to the closure with the most. Since the assembled were wine industry professionals with well-developed palates, they were quick to size up the samples and offer opinions.

As is often the case, tasters had their own ideas about which wine was best. But there was one thing not up for debate: The wines definitely didn’t taste the same.

“Pretty big difference, right?” Kim said with a smile as astonished tasters remarked on how three otherwise identical wines could seem so diverse.

None of this surprised Edina Kiss, the Europe-based product manager for Nomacorc’s Wine Quality Solutions business, who has run hundreds of similar tastings—dubbed “Taste the Difference”—for both wine professionals and casual consumers.

The program started a few years ago when Nomacorc, a leader in synthetic corks, reached out to wineries to ask them to run bottling trials. The idea was to take the same wine—bottled on the same date and under the same conditions—using three different wine closures, each with different oxygen permeability.

These studies have since been run with all kinds of closures, including natural and technical corks, screw caps, and synthetics, and the wine has subsequently been tasted at different time intervals. The goal of these experiments is not to prove that one closure tops another, but to underline the importance of the closure, period. This little piece of the wine package often gets overlooked.

“The main message of the program is to demonstrate the difference in the glass,” said Kiss. “We can tell nice stories about our closures, but at the end of the day, for the consumer what really counts is in the glass.”

Sauvignon Blanc that hasn’t been oak-aged is a great test wine. It’s fresh, fruity, and aromatic, and, said Kiss, “We can really taste and see that lower oxygen ingress can preserve these fruity aromas much better than a high ingress.”

You don’t have to wait all that long, either. “Typically, with white wines, after six months we can already see nice differences,” said Kiss. “The same goes for rosé wines.” Red wines take a little longer, and differences tend to be more about texture than aromatics.

Even people who’ve never heard of oxygen transfer rate, or OTR, can tell there’s something going on with the wines. “Consumers are able to tell,” said Kiss. “Sometimes they are not able to tell what the difference is exactly, but they are able to tell this wine is different from that one.”

In the tasting trials, wines are poured blind, and consumers are asked first to name their preference and then to describe differences, if they can—and most of the time they can. Finally comes the big reveal.

“It’s not like there is one good choice or one good answer, because, as you know, wine tasting can be very subjective,” Kiss pointed out.

She’s also run this exercise with winemakers to demonstrate how a small change in oxygen ingress can have a big impact on taste.


“Sometimes winemakers think they want a very tight closure, but then it turns out maybe a tiny little bit of oxygen can help.”

The Schug winery trials involved a relatively new Nomacorc product, Select Bio, which BioCorc_New2.0is made from sugar cane-produced bio-ethanol and is the first synthetic wine closure with a zero carbon footprint.

The two wines tested at the Innovation + Quality conference were Schug’s 2013 Sonoma Coast Sauvignon Blanc and their 2011 Heritage Reserve Pinot Noir. The standard bottling of the Sauvignon Blanc uses Select Bio 100, while the Pinot Noir uses natural cork.

So for the purposes of this trial, Schug tested the Sauvignon Blanc with Select Bio 100, Select Bio 300, and Select Bio 500. The Pinot Noir was tested with natural cork, Select Bio 100, and Select Bio 300. (Nomacorc’s model numbers don’t directly correlate to the oxygen transfer rate, although higher numbers do indicate more ingress.)

To my palate, the Sauvignon Blanc sealed with a Select Bio 100 was markedly more aromatic and zippier than the other two, with a burst of fresh and lively grapefruit bolstered by a warm lemon finish. The Sauv Blanc under Select Bio 300 was softer, and the Select Bio 500 softer still.

Kim noted that “the 100 was doing exactly what we intended it to do, one year out. Our goal with the Sauvignon Blanc is to have a wine that is vibrant with steely acidity and have more stone fruit minerality. The 100 was preserving these characters to me personally and, again, it was doing exactly what we asked it to do.”

On the Pinot Noir side, the natural cork wine had more vanilla and baking spices in the aroma compared to the Select Bio 100, which had a softer aroma. The Select Bio 300 appeared to show a more developed wine.

Schug agreed to participate in the trial for a couple of reasons, notably because of their strong relationship with Nomacorc, said Kim. “We think their products are really solid. And on the people side of things, we really like working with those guys because they are really easy to deal with and always willing to help.”

Plus, given their use of Nomacorc Select Bio 100, they’re interested in learning all they can about the effects these closures have on their wine. The Select Bio 100, 300, and 500 are tailored to achieve specific results, and Schug stood to learn a lot from a controlled trial in which the only variability was the closure.

“We’re able to see how the wine will develop at a specific date and time,” said Kim, “and that’s pretty impossible with a natural cork.”

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