http://m.brisbanetimes.com.au/wa-ne...-the-physics-of-champagne-20131224-2zw0t.html
If you're unlucky enough to get hit in the face by an errant champagne cork this Christmas, console yourself with the fact that it could be a lot worse.
Scientists have discovered that the energy that launches the cork across the room accounts for only 5 per cent of the total energy released when opening a bottle of bubbly.
The vast majority of the energy is dissipated as sound - the famous pop as the carbon dioxide forces the cork out of the bottle's neck.
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The study, by French scientists (of course), showed that this ratio remains the same regardless of whether the champagne is served chilled or - quelle horreur! - at room temperature.
But the cork's speed, and the amount of carbon dioxide released, both increase with temperature, reported Gérard Liger-Belair of the University of Reims Champagne-Ardenne and his colleagues.
The researchers opened bottles of champagne at 4C, 12C and 18C, and used high-speed infra-red imaging to study the cloud of carbon dioxide released when the cork pops.
At 4C, the cork is launched at just under 40km/h, while at 18C its muzzle velocity is almost 55km/h, the researchers reported in the Journal of Food Engineering.
As any connoisseur knows, champagne is best drunk between 7C and 9C. And the results show that, besides being a crime against good taste, warm champagne is a greater injury risk because the cork flies out at a higher velocity.
"Every year, the combination of warm bottles of champagne or sparkling wines with careless cork-removal technique results in serious eye injuries and even permanent vision loss," Professor Liger-Belair and his colleagues wrote.
It's no surprise that the explosion packs a punch, given that a standard 75 cl (750mL) champagne bottle is crammed with the equivalent of 5 litres of carbon dioxide.
Sugar added late in the fermentation process turns into carbon dioxide inside the sealed bottles, forming a 'supersaturated' solution that generates bubbles when the pressure is released.
The researchers also pointed out that it is possible to open a champagne bottle more gently, by releasing the cork gradually rather than firing it across the room.
However, even the experts admit that popping the cork is more fun. "Even if it is far safer to uncork a bottle of champagne with a subdued sigh, most of us would admit to having popped open a bottle of champagne with a bang," the researchers wrote.
In fact, seemingly the only question left unanswered by their research paper is what happened to all the leftover champagne after their experiment.