How long does an open bottle of wine last? The countdown begins

The moment the cork leaves the neck, the bottle stops being a cellar object and becomes fresh produce. Not as perishable as milk, but not as eternal as we would like either, when two glasses are left and the evening is over. Anyone who leaves half a litre of red on the counter to “finish tomorrow” is placing a bet, and almost always loses it without noticing: the wine does not suddenly become undrinkable, it fades a little at a time.

The enemy is called oxygen

A little air, at first, does good: it is the reason we decant a young, closed red. The trouble is that oxygen does not know when to stop. After a few hours the fresh-fruit aromas begin to fade, then come notes of cut apple, dried fruit, stewed fruit. In whites the colour shifts towards gold, in reds towards brick. This is oxidation, the same reaction that turns a peeled apple brown.

Then there is a second, more insidious process: acetic bacteria, which in the presence of air turn alcohol into acetic acid. It is the road to vinegar, and you recognise it by a pungent smell, almost like nail varnish. At that point there is nothing left to save, except perhaps the vinaigrette.

All of this depends on three variables: how much air is left in the bottle, what temperature it is kept at, and how well equipped the wine is to defend itself. Acidity, tannin, sugar and alcohol are its armour. A young, tannic, acidic red holds up better than a delicate, already mature one; a lively white lasts longer than a soft, oak-aged one.

A rough calendar (very rough)

The figures that follow are those that circulate most consistently among the trade’s guides, but they should be taken for what they are: orders of magnitude, not expiry dates. A bottle still three-quarters full behaves differently from one with a finger of wine at the bottom, and a kitchen in August is not a cellar.

Sparkling wines. With a proper stopper and in the fridge, usually one, two or three days. Metodo classico wines, the Italian traditional-method sparklers, which start out at a higher pressure, tend to hold up a little better than lighter Martinotti-method wines. After that, the wine remains drinkable but loses exactly what you opened it for.

Whites and rosés. Fresh, light ones, stoppered and in the fridge, can last around five days, though they give their best in the first twenty-four hours. Fuller-bodied whites and oak-aged ones are generally more fragile: three or four days is already a generous estimate.

Reds. Between three and five days, with considerable variation. A young, tannic red sometimes improves the next day; a light Pinot Nero or an old, already fragile red can collapse within hours. For very mature wines the rule is simple: open them when you are sure you will finish them.

Fortified wines. Here the rules change, but not across the board. A Marsala, especially in its older versions, is born into an oxidative world: it has alcohol and often sugar on its side, and once opened it can last weeks, sometimes even longer, losing something in freshness without going off. Much the same goes for Madeira and for oxidative-style Sherries. Beware, though, of Fino and Manzanilla, which are aged under a veil of yeast and, once opened, should be treated almost like a delicate white. And a vintage Port, after decades in bottle, is no larder staple: it must be drunk quickly.

The teaspoon in the sparkling wine: the story of an illusion

It is Italy’s most widespread grandmother’s remedy: a teaspoon, ideally silver, slipped handle-first into the neck of a bottle of sparkling wine. The popular explanation wavers between improvised physics (“the metal cools it and holds in the gas”) and pure faith.

The evidence, however, points entirely the other way. According to several popular-science sources, in the mid-1990s both a group of students at Stanford University and the Comité interprofessionnel du vin de Champagne compared opened bottles with and without a teaspoon: the presence of the spoon made no appreciable difference, whereas an airtight stopper did. The methodological details of those tests are not easy to reconstruct, but no study appears ever to have shown the opposite.

So why does the myth endure? Probably because bottles with a teaspoon almost always end up in the fridge, and cold genuinely does have an effect: carbon dioxide dissolves better in cold liquid, and the bottle loses its gas more slowly. The credit belongs to the fridge; the teaspoon merely takes the applause.

What actually works

The right stopper. For sparkling wines you need a pressure stopper with wings that clip onto the neck: it is the only accessory that holds in the gas in any meaningful way. For still wines their own cork will do, put back the way it was already in contact with the wine, or else a silicone stopper.

The fridge, reds included. It is the simplest piece of advice and the most ignored. Cold slows both oxidation and bacterial activity, and that goes for a Barbera as much as for a Vermentino. Just take the bottle out half an hour before serving to bring it back to temperature.

Decanting into a smaller bottle. It is the most effective trick and the cheapest. The problem is not the air that gets in afterwards but the air that stays inside: half a litre of wine in a 0.75 bottle shares the space with a quarter of a litre of air. Poured into a clean half-bottle, filled to the brim and tightly closed, it has almost none. A washed 375 ml bottle kept for the purpose is the most underrated wine accessory there is.

The vacuum pump. It removes some of the air and does some good, but less than the packaging promises: the vacuum you can achieve by hand is partial, and some argue that the suction also draws off a little of the aroma. There is no solid evidence either way on the extent of this effect. What is certain is that it is useless, indeed counterproductive, with sparkling wines.

Inert gas. Canisters of argon (sometimes mixed with other gases) spray a gas heavier than air into the bottle, which settles on the wine like a blanket. It works better than the pump, provided you use it properly and reseal at once. The same principle underlies the systems that draw wine through the cork with a needle without ever opening the bottle: expensive, but for anyone who drinks important bottles a glass at a time, they genuinely change the rules.

The best preservative is still thirst

All these tricks buy time, not immortality. An open wine is a countdown, and the only sensible question is how to spend the days that remain. The answer, in our view, is to stop treating leftovers as a problem to be hidden at the back of the fridge: a white on its third day can end up in a risotto, a tired red in a slow-cooked stew, and a Marsala opened a month ago is simply a Marsala waiting for the right dessert.

As for the teaspoon, leave it in the drawer. Or use it for what it does superbly: stirring the sugar into the next morning’s coffee.

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