Basically, there’s a reason why most wine isn’t in boxes: The materials used to make that packaging possible is notorious for messing with the flavorful compounds of the liquid. In particular, the ethyl butyrate and ethyl hexanoate compounds, which can give drinks fruity flavors, are either absorbed by or allowed to completely escape through polyethylene — the plastic that makes up the bag inside those boxes.
Food companies first became aware of the phenomenon when they realized that juices completely lost their taste after being stored in some kinds of plastic for too long; polyethylene storage is a common culprit.
However, boxed wine is still wine. And, we won’t argue with that. (io9)