Factors of Taste: Results from a Special Tasting at the Digital Wine Communications Conference

Can we always tell what makes us like or dislike a wine? How much of it has to do, strictly speaking, with the grapes and the winemaking? And, do we always understand exactly why a wine is showing well or not?

As demonstrated by a special wine tasting held at the most recent Digital Wine Communications Conference (DWCC) in Montreux, Switzerland, with financial and organizational support from Nomacorc, the answers to these questions are more complex than you might think—even if you’re an experienced taster. First of all, there are questions of personal taste, which can vary considerably. And second, some unexpected or extraneous factors can come into play and affect our perceptions.

How it worked

The DWCC tasting brought together over 200 participants—wine writers, bloggers, professionals in wine communications and others—who were asked to evaluate wines in four different flights, without being given any details about what they were tasting. Participants were also told to avoid discussing the wines with their neighborsDWCC14.

Conducted by UK wine writer Robert Joseph and Nomacorc researcher Maurizio Ugliano, with logistics and support on sensory questions respectively provided by Katie Myers and Antoinette Morano, also from Nomacorc, the event was meant to build the participants’ awareness of factors that can influence or even distort impressions.

“There is no right or wrong, here,” both Joseph and Ugliano repeated several times during the session, emphasizing that the point was understanding first and foremost the conditions that play with perceptions. At the end of the tasting,  Joseph and Ugliano offered examples of studies that showed how each of the presented factors operates.

Each flight was meant to isolate one particular factor: exposure to oxygen, levels of residual sugar, the presence of Brettanomyces, and the presence of cork taint (TCA). All wines used were bottled under Nomacorc closures to avoid variations in oxygen ingress or the presence of random cork taint that could have affected the results. For the cork taint and Brettanomyces tastings, controlled amounts of the required components were added before the tasting to fault-free wines, in order to produce levels of those components that corresponded to specific sensory thresholds.

For each factor, participants were asked to describe which wines they liked best, and also to select from a series of descriptors like “dry,” “rich,” and “fruity” (as many as fit the bill). Results were correlated with a “taste profile” for part of the participants who had answered a survey defining their tasting preferences.

Surprise, surprise!

Just judging from the sounds—and sometimes loud conversations—heard in the room after the nature of each flight was revealed, the tasting certainly surprised a lot of the participants. The flight focusing on sugar levels, in particular, caused a fair DWCCFlavor_Support2number of reactions as people discovered that the fruity wine they had tasted was perhaps more sweet than fruity: one wine had barely 2 grams per liter of residual sugar, the second one had 7 grams of residual sugar, and the third one 17 grams of residual sugar. Preferences went largely to the drier wines (with 42% of tasters preferring the wine with two grams of sugar), but clearly, the amount of sugar in the last wine (which is sold as a regular table wine) caused some to pause.

The Brettanomyces tasting also surprised many, as preferences among the wines were more evenly split (41% of participants expressed no preference, in fact). Brett is most often presented purely as a fault, something that was probably hard to reconcile, for many, with the fact that they still found the most bretty wine interesting. In fact, a higher number of participants indicated that the brettier wine was “complex,” when choosing descriptors from the provided list.

Seeking closure

The “oxygen” component of the tasting focused on a 2012 Eberle Viognier from California. All wines poured were bottled the same day, under the same, controlled conditions, with the only difference being DWCCFlavor_Support3the closure used. More specifically, the wines were using two different versions of the Select Series Nomacorc closures. The first wine was under Select 100, the tightest of the Select closures, which had let 2.2 milligrams of oxygen into the bottle since bottling in the spring of 2013. The other one, bottled under Select 500 closures, had let in 4.2 milligrams of oxygen since bottling.

49% of participants preferred the wine with the tighter closure, 29% the one with the more permeable closure, and 22% expressed no preference. A slightly higher number of tasters described the wine with the tighter closure as richer and more complex, a result that can be seen as correlating with a young Viognier’s expressing more of its bright, tropical primary aromas, since oxygen probably affects the aromatic components implicated in those aromas.

Whatever the preferences, it is interesting to notice that impressions of both wines did vary noticeably, just on the basis of a small difference in oxygen exposure. “These experienced wine tasters were able to tell obvious differences between two wines for which the only difference was the closure,” commented Nomacorc principal sensory technologist Antoinette Morano, after looking at the results. The result is particularly striking since the difference in oxygen transmission rates between the 100 and 500 Series is less than the average variation between two natural corks; tests performed by Nomacorc have shown that the variation within a same batch of natural corks can reach over 10 milligrams of oxygen per year.

Tainted love

In the cork taint flight, the same wine, a Sauvignon Blanc, was served to participants DWCC14with various levels of voluntarily added TCA: the first wine had no TCA, the second wine 1 part per trillion (below normally detectable thresholds), and the third wine 2 parts per trillion, the threshold of detection for most people. Not too surprisingly, the majority of this experienced panel of tasters did note that the TCA-spiked wines were in fact corked.

The surprise, however, might be that 8% of participants still declared preferring the third wine—the one with the most TCA. Cork taint is unanimously seen as spoiling wine, so what could be going on here? “Some people have higher thresholds for identifying TCA,” explains Morano, “and some are even completely anosmic to it, meaning that no matter how much there is, they are simply unable to identify it specifically.”

Without being able to put a name on it, however, people would still be affected by the presence of cork taint. Recent studies have shown that TCA blocks olfactory receptors, even when its level is below human detectable thresholds. As a result, aromas are dulled and less perceptible, even if “corked” wouldn’t be used as a descriptor by the taster.

In sum

So what makes a wine “good” or “bad” to you? Although far removed from everyday wine-drinking conditions, the tasting performed at DWCC helped highlight a number of factors that can play with our reactions to a wine. Isolating individual factors may be a bit artificial—and unpleasant, even, in the case of TCA—but it is a very useful way to better recognize what is going on when you’re tasting.

Editors Note: An article by Robert Joseph providing the full details of the tasting results will be published in 2015.

Photo Credits: DWCC & Ricardo Bernardo

About the Author

Rémy Charest is a Quebec City-based journalist, writer, and translator. He has been writing about wine and food since 1997 in various Canadian and American print and online publications, includijng Le Devoir, Le Soleil, Coup de Pouce, EnRoute, Palate Press, Punch Drink, WineAlign and Châtelaine, and has been a regular radio columnist for Montreal's CJAD and CBC/Radio-Canada. He is additionally a wine judge for national and international wine competitions, notably the National Wine Awards of Canada and the World Wine Awards of Canada organized by WineAlign.

Rémy Charest Photo Credit: Jason Dziver


  1. That was an interesting session! Thanks for organising this. I found it interesting that there were some advocates in the session who believed that TCA was present in all the wines of that flight, even though the control one had none. With a small percentage of tasters also claiming ‘false positive’ responses for TCA when none is present, there’s clearly an issue there for the wine sector to consider!

    1. Thanks for the comment, Damien. I think that once TCA gets into your nose, it’s kind of hard to get it out! Which might explain why, smelling back to the first wine after smelling the last one in that flight, you might figure there is TCA in there too. In a fully controlled sensory tasting, you’d get the wines one by one, no going back, which would make calibration of thresholds and overall impressions more precise.

Leave a Reply