Lovers of Champagne, Prosecco and all things bubbly will be familiar with one age-old struggle: how do you keep it fizzy?
On the (rare) occasion that you’re unable to finish a bottle of the good stuff, you’re left wondering what the best way is to preserve those tasty bubbles. Some people use a stopper, others wrap the top in foil, some don’t cover it with anything and others use a spoon. Yes, a spoon.
You’ve probably heard of the spoon-in-the-bottle trick, a rumour as divisive as how to make a proper cup of tea. Whether you’re a firm believer or a staunch sceptic, we’re here to see if there’s any science behind this old wives’ tale.
What is the Spoon Trick?
In case you haven’t heard, the spoon trick is a common way of keeping your leftover champagne as fizzy as possible. The theory goes that when you pop your unfinished bottle of bubbly in the fridge, a sure-fire way to keep that delicious effervescence is to place a metal spoon handle-first into the neck of the bottle. That’s it – no cork, no stopper and no foil.
This trick has been tested several times in the past. It has been validated and it has been disproven, but what we want to know is how science gets involved in such a controversial topic.
How Does it Work?
When a metal spoon hangs in the neck of a bottle, it causes the air inside to cool very quickly which eventually leads to an airlock. This is because of the thermal conductivity of the metal.
Conductivity of Metal
Metals are good heat conductors because of their molecular structure, which is comprised of closely-packed metal ions. These ions are arranged in a symmetrical and ordered structure known as a lattice.
As well as this, metals also contain delocalised electrons which carry kinetic energy throughout the lattice, causing the ions to constantly vibrate. This is another reason why metals, including objects like spoons, are excellent conductors of heat.
The reason that the spoon is able to cool down the air inside the bottle so quickly is because of its conductivity of heat energy. Heat energy isn’t always associated with something being hot. In fact, coldness is actually a measure of heat transfer. This is because cold energy doesn’t exist; an object can only become colder when heat energy moves away from it. This is exactly what is happening with the spoon in the champagne bottle.
Because it’s a good conductor, the metal spoon is able to suck the heat energy from inside the bottle. Since heat energy always moves from something hot to something colder, the heat conducted by the spoon is then lost to the atmosphere of the fridge.
This means that the air in the bottle will match the temperature of the spoon and the fridge, and this is why the spoon is able to cool the air in the neck of the bottle extremely quickly.
When all of this happens, it creates an airlock in the neck of the bottle. This is caused by the rapid cooling of air. Cold air is much denser than hot air because its molecular bonds don’t absorb much energy. As a result, the molecules in the cold air are closer together and don’t move very much. Hot air, on the other hand, absorbs a lot of heat energy which causes the molecules to move and expand. This decreases the density of the air.
This is why hot air always rises while cold air stays at the bottom. This is also why the cold air created by a metal spoon eventually forms an airlock. The density of the cold air means that it won’t rise and instead will sit in the neck of the bottle. This is what prevents those glorious bubbles from escaping.
Why Keep Champagne in the Fridge?
If you were to put a spoon in your champagne and leave it on the kitchen counter, it wouldn’t be long before it went flat. Storing your bubbly beverage in a fridge is the most important part of preserving its effervescence.
You should keep your champagne in the fridge because at low temperatures, carbon dioxide gas (which makes your drink fizzy) has much less kinetic energy. Therefore, it won’t move around much which makes it less able to escape.
At high temperatures, the liquid molecules in the drink move very quickly and escape. Since gases are more mobile than liquid molecules, these will also gain a lot of kinetic energy and escape even quicker.
By keeping your fizzy tipple in the fridge, you’re giving those gas bubbles the best chances possible at survival. In fact, Stanford University Chemistry Professor, Richard Zare, stated after his spoon-in-the-bottle investigation that it is more effective to leave an open bottle of champagne in the fridge without covering it all.
So, it seems there’s some scientific truth to the rumour. But that doesn’t mean that this piece of folklore is bulletproof, or immune to controversy.
Experiments have been carried out plenty of times in order to discern the most effective way to preserve champagne. In many of these, the spoon trick actually proved to have little effect on the bubbliness of the drink.
While some recorded that there was no difference between using a spoon or cork to preserve champagne, the team at Mythbusters quite definitively shot down the spoon trick by ranking it last in their blind taste-test of which champagne was preserved the best.
But if there’s a scientific base to this theory, then why has the spoon failed so many people? It may all come down to personal taste and how each human experiences things differently – so if the spoon works for you, why fix something that isn’t broken?
The next time you find yourself popping that cork off your favourite champagne, why not test this theory out for yourself? If you can stand to leave some behind, that is! At ReAgent, we love looking a little closer at the science behind everyday life. Never skip a beat by signing up to our free newsletter, where you can receive all the latest and greatest chemistry facts!