Bag in a box

Bag in a box is a method of wine packaging which consists of a bag, usually made of mylar or other plastics, filled with wine and protected by a box, usually made of cardboard. The bag is sealed by a primitive plastic tap, which is revealed by tearing away a small piece of cardboard and used to dispense the (usually cheap and unlpleasant) wine.

The chief advantage to bag in a box packaging for wine is that it prevents oxidation of the wine as it is dispensed. Whereas wine in a bottle is oxidized by the volume of air in the bottle which has displaced the wine already poured, wine in a bag is never touched by air and thus never subject to oxidation until it is put in a glass. Thus, bag in a box packaging is not inferior per se, but is simply preferred by producers of cheap, inferior wines such as Franzia because it is inexpensive. If prestige wines were packaged in bag in a box, they would not be subject to cork taint nor to spoilage due to not drinking them quickly enough after opening.