Boxed wine is a wonderful thing. It’s perfect for a large group, or to have in the house for a glass or two with your meal when you don’t want to open a bottle. And the wine inside the box keeps getting better and better; gone are the days when your only option was Franzia. Now, there are great options for whites, rosés and light reds that come inside boxes, and they are begging to be enjoyed.

But just because you can’t see the wine inside the box doesn’t mean it will last forever. Just like uncorking or unscrewing a bottle, after you’ve “tapped” a box of wine, there is a definitive window of time that the wine will still taste great. It’s definitely a much larger window than for the wine inside an open bottle, but it’s not indefinite. Boxed wine can turn to vinegar just like wine inside an open bottle can.

The first step when it comes to maintaining freshness is storing your open box of wine in the fridge. This storage method will slow the wine’s exposure to oxygen and help maintain freshness. After you’ve gotten the box inside the fridge, some people might tell you the wine is good for up to three months, but sadly, that is not the case. Most experts agree six weeks is really the longest you should take to finish a box of wine, but two to three weeks is the sweet spot. This length of time will ensure that your last glass of wine is definitely as fresh as your first. It’s a longer length of time than an open bottle stored in the fridge, which has about three to four days, max — but not so long as to allow you to forget about it in the back of the fridge.

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Keep in mind as well that any box of wine you purchase should be opened and consumed within a year of purchasing. Wine inside a box not only doesn’t age, it also micro-oxygenates. While the bag it’s stored in is pretty good at protecting it, a small amount of oxygen will still slowly slip in, and after a while you will have vinegar, whether you opened the box and poured yourself a glass or not.