麻豆传媒

Does putting a teaspoon into an open bottle of champagne really prevent it from losing its fizz, and if so, why?

Mark Thompson
Tewkesbury, Gloucestershire, UK

Placing a teaspoon handle down into the neck of an open bottle of champagne is a common hack to help preserve its fizz.

The idea behind this method is that the spoon, due to its metal composition and its handle鈥檚 cooler temperature, can help maintain carbonation by reducing the escape of carbon dioxide bubbles from the champagne.

However, the scientific evidence supporting this method is limited. It is possible that the spoon acts as a barrier, preventing immediate CO₂ release, but it may not significantly affect the champagne鈥檚 fizz over an extended period.

The most effective way to preserve champagne or any carbonated drink鈥檚 fizziness is to reseal it with an airtight stopper and then store it in the refrigerator.

Damir Blazina
Chester, UK

The spoon makes no difference. This question has become an urban legend and shows how easy it is to be misled by an uncontrolled experiment. People observe that their half bottle of champagne with a spoon in the neck is still fizzy the following morning, but, in reality, a champagne bottle keeps its fizz for several days with or without the teaspoon.

The bubbles in champagne and other sparkling wines are CO₂. In traditional m茅thode champenoise production, the wine undergoes two fermentations: one before bottling and one in the bottle. The second fermentation produces the bubbles that are vital for the flavour of the final product.

The process produces some 7.5 grams of CO₂ in an average 0.75-litre bottle of champagne. Because the bottle is sealed, the gas dissolves in the wine to reach an equilibrium with the (very small) headspace above it and leads to quite a high pressure in the bottle: about 6 bar (90 psi) for champagne, somewhat less for other sparkling wines. This is why champagne bottles are so thick.

When the bottle is opened, the gas in the headspace can expand into the atmosphere, giving its characteristic 鈥減op鈥�. The dissolved CO₂ can now escape from the wine, eventually reaching a level that matches the amount in the atmosphere, of about 1.3g in a 0.75-litre bottle. The bubbles are a sign of this process, which isn鈥檛 instantaneous: its rate depends on the ambient temperature and the surface area of the liquid that is in contact with the atmosphere. For a champagne bottle with a narrow neck at room temperature, it takes several days. A bottle of champagne opened in the evening will therefore still be bubbly the next morning, and probably for three to four days after that.

The spoon in the neck makes no difference, as can be shown by storing two open bottles, one with and one without a spoon. More reliable ways to limit the loss of bubbles include refrigeration to slow down this process, and using a sparkling wine stopper that prevents the CO₂ from escaping the bottle and recreates the equilibrium between the liquid and the headspace above it, causing the gas to re-dissolve.

For more detail, I can refer your readers to 麻豆传媒鈥榮 book (2007), which addresses the question on page 28 and details a controlled experiment to prove that the spoon has no effect. I would only add that those of us fortunate enough to be of legal drinking age in our respective jurisdictions can (responsibly) enjoy the sparkling wine throughout the study 鈥� not something that every chemistry experiment can offer!

David Muir
Edinburgh, UK

No, it doesn鈥檛. In fact, the wine may lose its fizz even faster, as scratches and pits on the surface of the spoon will increase the number of nucleation points in contact with the wine. Nucleation points are tiny surface aberrations that cause the gas within drinks to be released more easily. Look at any glass of fizzy drink and you will see streams of bubbles originating from particular spots on the glass 鈥� these are nucleation points.

This question begs another: why open a bottle of champagne if you aren鈥檛 going to finish it?

To answer this question 鈥� or ask a new one 鈥� email lastword@newscientist.com.

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