Wine degrades, or oxidizes, due to the reaction between the delicate aromatic compounds in wine and oxygen. Heat speeds up these reactions. Excessive heat causes a whole slew of additional problems, but I’m making the assumption that you are careful enough not to cook your wine.
So how should you handle that bottle of wine you didn’t finish? Let’s explore your options.
Photo courtesy toddwickersty via Flickr/CC
Put a Cork in It
This is surprisingly a very viable option, particularly for young wines. The amount of oxygen your wine absorbs is not really governed by whether the bottle is corked or not. There is more oxygen in the headspace (the empty part of the bottle) than your wine is able to absorb over night, so corking the wine does little in that respect. It does keep flies and debris out though, so I always recommend corking up your bottles for the next day.
What does govern the rate of oxygen absorption? Surface area. The greater the surface area exposed to oxygen, the higher the rate of absorption.
So putting a cork in the bottle and leaving it out on the counter is not a terrible way to treat your wine, particularly with younger wines that can use some softening and evolution in the bottle. Still, it’s not the best way.
Photo courtesy cbcastro via Flickr/CC
The surface area is what potentially kills your wine, so what are you going to do about it? Well, I may have oversimplified things a bit by focusing solely on surface area. While surface area is the most important variable by far, the ratio of surface area to volume needs some attention as well.
A wine typically is fairly uniform for about two-thirds of its height, but I’m going to suggest different treatments for a bottle four-fifths full and three-fifths full. Why? Two issues spring to mind. The first being that the fuller bottle has a great volume of wine, allowing for great absorption of oxygen to result in the same evolution for the wine. Consider the extremes, if there was only one millimeter of wine spread over the bottom of the wine bottle and oxygen absorption would pretty much flood the wine, while if there were 200 millimeters that same amount of oxygen would barely effect the wine.
Photo Courtesy DCeventjunkie via Flickr/CC
So Surface Area Counts
It does, but there’s also another factor worth mentioning. The less wine that is in the bottle reflect that more wine has been poured out of the bottle. With each pour, the sloshing back and forth of the wine introduces oxygen. While we should be concerned with the transfer of oxygen to the wine after we are done with it, we also have to be aware of how much oxygen is introduced to the wine while we pour it.
This is why my favorite wine preservation technique is entirely proactive. When I think I am not in the mood to finish a bottle of wine, the first thing I do with the freshly opened bottle is to pour it in a clean half-bottle that I keep just for these purposes.
By filling up a half-bottle like this, I am minimizing the surface area of the wine while at the same time minimizing the introduction of oxygen into the wine. A perfect recipe for best-case scenario wine storage!
Photo courtesy yashima via Flickr/CC
Bringing the Heat
I don’t stop there. That full half-bottle goes straight into the fridge. It’s not that I like all my wines chilled, but recall that the interaction of oxygen with the wine is stimulated by heat. Keeping the wine cool slows down the reactions, and that means your wine will remain fresher longer.
Photo courtesy jmcgrath via Flickr/CC
So How Long Will it Last?
It has been my experience that a half full bottle of wine will remain at peak or even improve for 12-24 hours after simply being corked and placed on my kitchen counter at 70 degrees Fahrenheit. After that, the wine tends to jump off a cliff rather rapidly, say in another 24-36 hours.
That same wine placed in the fridge sees about a doubling of each time stage, still at peak or improving for two days and drinkable for another two or three.
Pour half of the bottle into a half-bottle, cork it and place it in the fridge and you’ll end up with an almost new bottle, one that you can revisit for weeks and still thoroughly enjoy. I’ve even found a bottle a year later, don’t ask, and it was still delicious!
Photo courtesy josewolff
What About All the Gadgets?
First off, the best gadgets for wine preservation tend to be the simplest. Don’t have a half-bottle? There are still options. Consider adding volume to your wine in the form of marbles, ball bearings, or chunks of food grade plastic. If you don’t have a half-bottle lying around, I doubt you’ll have any of these, but it’s worth remembering that there is more than one way to solve the problem of surface area.
Another way to limit the surface area of the wine to oxygen is by covering the wine. This can be done in one of two ways, with a tangible physical barrier or with gas.
Tangible barriers, thin sheets of plastic that sit atop the wine in the bottle and are sold under the Wine Shield name, claim to keep wines fresh for up to four to five days. I haven’t tried this, keeping wine around for five days requires discipline, but I have used them for three days and they seem to work just fine.