This article was published in The 30 Second Wine Advisor on Monday, Dec. 18, 2006.

How long can you keep leftover wine?

How long can you keep leftover wine once you've opened the bottle? In my standard reply to this frequently asked question, I try to discourage folks from overdoing it:

The short answer, I'm afraid, is, "not very long." Wine, like fresh fruit, is perishable, and air is its enemy. Once you've taken out the cork and exposed the liquid to oxygen, it starts to deteriorate fast.

Wine shops sell preservation systems that suck the air out of opened bottles or squirt inert gases in, but I wouldn't spend the money or effort. They offer little if any advantage over simply jamming the cork back into the half-finished bottle. It will hold at room temperature for a day or two before its flavor starts to deteriorate seriously. Pop it in the fridge, and it might last for a week or two. Fortified wines like Port or Sherry may last a little longer, but much more than a week is pushing it.

Your best bet is simply to finish your wine within a couple of days ... use the leftovers for cooking ... or invite friends over to share.

That's my standard advice, anyway. But always being one to test the conventional wisdom - even my own - I ran a simple experiment. Over several nights, I took care to leave about a half-bottle of each evening's wine, casually stored on the kitchen counter with the corks stuck back in. I let them go for about five days before re-tasting, then checked them again after a full week or more had passed.

Of course the wines changed over time, but somewhat to my surprise, none of the three deterioriated as quickly as I thought they would, and all remained at least drinkable after a week to 10 days, and at least two of the three arguably became a bit more accessible with extended airing. Perhaps it's more than a coincidence that all three were fairly robust reds with at least limited cellar potential.

Here's a quick look at the three wines and how they fared in the open bottle:

Simon Bize 2002 Bourgogne "Les Perrières" ($16.99) - A simple Burgundy but a good one, it's clear, dark ruby in color, initially showing clear dark ruby color, attractive red-cherry aromas with a hint of smoke, and juicy and fresh flavors of tart fruit and crisp acidity in good balance. Four days later, its fruit had faded a bit, bringing its earthy character into sharper focus, which was not a bad thing. With clean fruit and crisp acidity, it was changed a little but just as good as new. Four days later, the first hints of incipient oxidation actually seemed to heighten the fruit and make the wine accessible, but I wouldn't hold it longer, as the first signs of the walnutty, "cheap-Sherry" character of oxidized wines were starting to show.

Domaine Paul Autard 2004 Côtes du Rhône ($14) - A hearty, "chewy" little brother to Chateauneuf-du-Pape, it's dark garnet in color with a reddish-violet edge. On first tasting, its aroma evokes Chambord raspberry liqueur, warm and ripe. Full-bodied, red-berry fruit and subtle earth and sufficient acidity are softened by abundant fruit and structured by slight, drying tannins, with 14.5 percent alcohol contributing body without excessive heat. Five days later it showed no hint of oxidation and in fact seemed to be shutting down and slosing a bit. Still, it was in no way deteriorating, with appealing black fruit and fragrant pepper on the nose and palate. Only the faintest touch of oxidation showed five days after that, emulating maturity rather than decay, and the fruit was opening up again in a ripe, structured wine. It's arguable that 10 days in the bottle actually improved this wine, although I wouldn't let it go much longer.

Sean H. Thackrey Pleiades XIII Old Vines ($23.49) - Featured in the Dec. 11 Wine Advisor, this fine California red blend earned my praise for its bold cherry-berry flavors, although I declared it a bit more fruit-driven and not quite as attractively earthy as some prior bottlings. After six days in the open bottle, however, it was much more like Pleiades of yore, with earthy and complex flavor nuances joining the fruit and only the faintest whiff of appropriate, mature-wine oxidation whispering at the edges.

Summed up, I still don't recommend keeping wine for weeks or longer once the cork has been pulled, and I'd urge erring on the side of caution by enjoying the rest of your bottle at the next reasonable opportunity. And do use the fridge to extend its lifespan a bit. But don't panic if you can't get back to the wine the next day. And remember, even if your wine gets too old to enjoy, it can't hurt you. Wine may lose its flavor and become flat, dull and unenjoyable after sufficient time in the open bottle, but it won't turn toxic.