THE QUESTION
How long does a box of red plonk tend to last, once opened, given that each contains about four litres when full?
THE ANSWER
Boxed wine – it's nice to know this newspaper hasn't lost touch with the common folk.
I believe this question is a sequel to a recent answer I tendered regarding the longevity of an open bottle. It was, of course, callously presumptuous of me to assume that all people drink wine from old-fangled glass containers. The answer is: pretty long.
Boxed wine, sometimes referred to as bag-in-box, contains a plastic bladder attached to an air-tight spout that protrudes from the cardboard carton. As you tap the spout to pour, the bladder collapses, just like those burp-free Playtex Nurser baby bottles. This minimizes the wine's exposure to air, and thus to the corrosive effects of oxidation, as it's dispensed.
A boxed wine can survive nicely for several weeks after opening. The bag offers a less-than-perfect hermetic seal, however. Small amounts of air get in over time, even if the box remains unopened. Typically, it's meant to be consumed within nine months to a year, and many boxes come stamped with best-before dates.
While it suffers from a down-market stigma, bag-in-box has other advantages, not least the fact that it weighs far less than the same volume of wine shipped in standard-size glass bottles. That means lower greenhouse-gas emissions related to transport. That red plonk you're consuming is relatively green. But, of course, you're drinking it for the great flavour, not the environment.
Have a wine question?
E-mail your wine and spirits questions to Beppi Crosariol. Look for answers to select questions to appear in the Wine & Spirits newsletter and on The Globe and Mail web site.