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Dear Dr. Vinny,

I have a question about corks vs. screwcaps. They used to say that cork, as well being a closure, also aided a slow oxidation over time, and obviously a screwcap cannot do that. I once asked a winemaker to comment, and he said, “We just don’t know.” Sure, with screwcaps there is much less spoilage, but as for the long-term effects, the jury is still out. I feel a bit sorry for the cork salesmen, as their trade seems to be on the way out. Any thoughts?

—Richard, Australia

Dear Richard,

“We just don’t know” is a pretty typical answer to the question of oxygen transfer into a bottle of wine sealed with a cork. There’s some evidence that corks allow a bit of oxygen to eventually reach the wine inside the bottle, but it’s not predictable, which is one of the reasons for bottle variation. Screwcaps are a bit more predictable—in fact, a winemaker can order screwcaps with calculated levels of “oxygen ingress.”

What does that mean for aging? I’ve participated in several verticals of wines bottled under screwcap (including a few comparing screwcap vs. cork), and I have to say I’m impressed. Under screwcap, wines seem fresher, and they do evolve, perhaps more slowly than under cork, retaining their fruit flavors longer. Screwcaps also eliminate the concern of dried-out, crumbling corks and TCA, that pesky flaw that can affect natural corks and the wines bottled under them.

That said, if I didn’t get to try those older wines under screwcap—and especially if I liked my wines with some bottle age—I can understand feeling uncertain about how my wines would age under a twist-off. For me, the jury isn’t out—I have a lot of confidence in screwcaps. In the end, I’m not going to pick a wine based on what kind of closure it has, and I’m not going to refuse to purchase a wine based on what kind of closure it has.

Don’t feel bad for the cork salesmen—keep in mind that there is more wine made now than ever, and there is still a demand for cork. There was a rumor going around a few years ago that there was a cork shortage, but that’s not true.

—Dr. Vinny

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