Do boxed wines contain more preservatives than bottled wines?

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Dear Dr. Vinny,

Do boxed wines contain more preservatives than bottled wines? Is that why they last longer?

—Marianne, Jeffersonton, Va.

Dear Marianne,

Actually, wines in a box age faster than bottled wines. The bags inside the box are semi-permeable, made from a type of plastic that allows minute amounts of oxygen exchange. There are actually “best by” dates stamped on most boxed wines, to enjoy them while they are still fresh, usually within a year or so. Bottled wines (in proper storage conditions) can hold up for considerably longer.

But boxed wines are really convenient, and their design naturally keeps the wine inside fresh for much longer than a half-full bottle of wine with the cork stuck back in. The reason most bottles of wine start to taste off after they've been open for a few days is that the wine starts to suffer from oxidation. With box wines, the plastic bladder containing the wine collapses as the wine is removed, so there's no oxygen introduced to the remaining wine as you serve it. If you open a bottle of wine and don’t finish it (let me pause for the “leftover wine, what’s that?” jokes out there), you would need to transfer the wine to a smaller bottle to get the same type of protection (check out our video for tips on storing leftover wine).

Boxed wines are convenient, durable and frequently good values (as are canned wines!), and let me remind you that you’ll further extend the life of an opened box if you keep it in the fridge.

—Dr. Vinny

Ask Dr. Vinny Aging Wine Boxes / cartons Packaging

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