To drink, or not to drink? The age-old conundrum: it’s midweek, the need for a glass of wine is already strong, but you know you’re not going to finish the bottle on your own and you definitely don’t want the rest to spoil.

So how long exactly will a bottle of wine last after opening? For those that crave a midweek boost to get them through, they're only options are half bottles or bag-in-box.

How long does wine last after opening?

The simple answer is that there is no definite length of time. On average, an open bottle of wine can last anywhere up to 5 days, with exact time depending on the way the wine was made and the way you treat it after opening.

As a general rule, red wines last longer than white wines after opening, their potential closer to five days while white’s is much closer to three. Meanwhile, sparkling wines, somewhat unsurprisingly given their effervescent nature, last the shortest and should be consumed within one to three days.

Why does wine spoil?

When it comes to preserving an open bottle of wine, oxygen is the enemy. While it is otherwise so useful in opening up certain wines (you’ll no doubt have heard the term allowing a wine to "breathe"), in this scenario contact with oxygen causes oxidation, basically turning wine to vinegar. (Learn more in "What Does it Mean to Let a Wine Breathe?")

The more oxygen in contact with the wine, and the longer the period of contact, the stronger the effects of oxidation. Or, put simply, the lower your chances of finishing that midweek bottle!

How to Preserve Wine

There are numerous techniques to combat the effects of oxidation, ranging from the absolute amateur to pricy professional gadgets.

First, we need to discuss proper treatment of bottles after opening.

Unless you’re drinking a high-end aged wine, the need for decanting or allowing the wine to breathe is pretty minimal. On the contrary, it’s only really going to be counter-productive in reducing the effects of oxidation. (Read on in "When to Decant a Wine.")

Therefore, be sure to replace the cork between glasses, and if it’s a wine that can be enjoyed chilled, store it in the fridge at all times.

Paper Towel

I know what you’re thinking: "this is not an option with sparkling wine corks." Fear not, and never underestimate the wonders one can work with a paper towel. Simply insert a tightly bound (cone-shaped) paper towel into the opening and hug the neck with the remaining exposed paper to maintain fizz and combat oxidation. Replace the wire cage over the paper towel. (It should look like a cape.)

Wine Stoppers and Wine Preservers

Alternatively, there’s an ever-emerging range of inexpensive sparkling wine stoppers that do an excellent job of re-sealing open bottles; perfect for that weeknight prosecco pick-me-up! The majority of these preserving caps can also be used on standard still bottles, and are much more effective than a cork if you don’t plan on reaching for the bottle for another few days.

As we mentioned earlier, the effects of oxidation are multiplied as the amount of oxygen in contact with wine increases: If you drink half a bottle, the remaining half will oxidize much faster than a bottle with just one glass missing.

In order to combat this, you could decant your half-empty bottle into an empty half-bottle (tongue twister alert), but it’s likely you don’t have many of those lying around. On the other hand, consider investing in an affordable vacuum stopper. These handy little gadgets are an effective means of sealing an open bottle, meanwhile allowing you to manually pump out some of the air that’s taken up empty space and currently oxidizing your wine.

It should be mentioned that these gadgets are inexpensive for a reason--they’re pretty primitive in their design and are never going to be 100% effective at halting oxidation. They will, however, extend the life of your open wine by a good few days and are definitely a worthy investment. Some even range at just $2.99 at discount stores, while others can be up to $50.

At the top end of the spectrum are high-tech gadgets which allow drinkers to siphon individual glasses of wine without spoiling the remnants of the bottle.

The needle-through-the-cork system replaces decanted wine with an inert (non-reactive) gas, completely unaffecting the wine left in the bottle. Yet, all this technology comes at a price--one which can only really be justified by restaurants or wine bars wanting to offer fine and rare wines by the glass. Suitable for a Tuesday night Pinot Grigio they are not!

Which wines last the longest after opening?

You’ve got your preserving cap--possibly complete with oxygen-removing hand vacuum - now it’s time to choose a wine.

Some wines are more susceptible to oxidation than others. Pinot Noir, for example, is highly sensitive and prone to quicker oxidation. Then there are organic and biodynamic wines, without the addition of extra sulfates (highly useful in the fight against oxidation), they’re good for a much shorter time after opening.

Without listing all of the varietals known to man, consider these general rules before buying a wine that you know you won’t consume in one go: