How long do you leave a bottle of opened wine in the fridge? The correct answer to this conundrum is (of course) “there is no leftover wine to put in the fridge”. But for those of you who cannot finish the bottle, how much time can you leave an opened bottle of wine lying around?

The uninspiring answer is “as long as it tastes good to you”.

When exposed to air, wine gets oxidised and starts to “taste funny”. Inside the bottle and before it is opened, the wine has very little contact with air. During the bottling process the winemaker displaces the remaining air between the wine and the cork (or screw cap) with an inert gas such as nitrogen or argon.

When the molecules that make up the wine are exposed to air, they start losing electrons, which changes their properties and makes them smell and taste differently. Once wine is exposed to air, bacteria also begin to consume the wine. A bacteria known as acetobacter starts to break down the alcohol (ethanol) in the wine, converting that alcohol to acetic acid, also known as vinegar. Oxidation and the conversion to vinegar are two separate chemical processes.

There are two things you can do to make your wine last longer. First, keep the wine exposed to as little air as possible, possibly by putting the cork back in the bottle. Second, slow down the metabolism of the bacteria by storing the wine in cold temperatures.

Typically, white wine can last up to a week in the fridge, while red wine lasts for three to five days.