Cap or cork, it’s the wine that matters most
Screw tops can nurture wine’s flavor just as well
SAN FRANCISCO — Don’t judge a wine by its cover. In a survey of the chemistry and flavor of pinot noir and chardonnay, consumers couldn’t discern wines capped with natural corks from screw caps, scientists reported March 25 at the spring meeting of the American Chemical Society. The results suggest that the way its bottle is stopped has little if any effect on a wine’s flavor.
“Wine quality should really be judged by the wine, not the cork,” said Michael Qian of Oregon State University in Corvallis, who led the research. “The right kind of screw cap is just as good as a cork, or even better, because it is more consistent.”
The permeability of a wine’s cork determines the amount of oxygen that enters the wine, and this acts on other compounds that affect flavor. Some traditionalists assert that real corks are the only way to get just the right amount of healthy gas exchange needed for a flavorful wine, while screw caps are suffocating. But Qian’s survey found that wine was just as appealing to taste testers whether it was aged in bottles topped with screw caps or traditional corks. And instead of stifling the wine, one kind of screw cap and the synthetic cork actually did the opposite, allowing the wine to breathe too much.
Working with Qian and colleagues, graduate student Juan He investigated 2006 vintage pinot noir and chardonnay from the Argyle Winery in Oregon. The winery closed 150 bottles each with natural cork, synthetic cork and three screw caps, each with a different lining. Every six months for two years the team uncorked bottles from each of the five groups to test the chemical profile and dissolved oxygen content of the wine under each type of seal. The researchers also had volunteers rate the flavor and aroma of wine from the different kinds of capped and corked bottles.