Are preservatives injected into wine corks through the foil capsule?

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Dear Dr. Vinny,

A friend told me that preservatives are injected into wine corks through the foil capsule or plastic sleeve, as indicated by the small holes in the seal. This seems unlikely to me. Is it true?

—Catherine, West Palm Beach, Fla.

Dear Catherine,

Those tiny holes in the capsule sure cause a lot of confusion! No, they are not a sign of something injected into the bottle, nor are they there to let the cork breathe.

Rather, those tiny perforations act as a vent to allow air to escape when the capsule is being put on the bottle. They allow for a tighter, wrinkle-free fit without any air trapped in the capsule.

—Dr. Vinny

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