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Dear Dr. Vinny,

While reading an article on cork closures vs. screwcaps, I came across something about sulfide reductions. What detrimental effects does sulfide reduction have on a wine?

—David C., Toronto

Dear David,

A wine with a sulfide reduction is easy to pick out: volatile sulfur compounds smell like rotten eggs, rubber, struck matches, skunk, sewage or rotten cabbage. Yummy, right?

In the battle between corks and screwcaps, cork proponents have been saying for some time that wines bottled under screwcaps are more affected by sulfides, and less so with corks. The pro-cork movement claims that cork minimizes the problem of reduction by allowing oxygen to leak into the wine, which reacts with sulfides and dissipates the off odors.

But more research is coming out that says if you want to avoid these bad smells, all a winemaker has to do is avoid or remove sulfides before bottling, no matter what the closure. If you sense these taints in a wine, it’s not the closure’s fault, but the winemaker’s fault.

—Dr. Vinny

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