Physicists take champagne to work
Champagne bubbles rise to the top of the glass in a mathematical pattern that changes over time, say French and Brazilian researchers.
The researchers took snapshots of a glass of freshly poured champagne and looked closely at the patterns of carbon dioxide (CO2) bubbles that evolved.
First, they saw pairs of bubbles rising in strings. But over time, the bubbles rose in groups of three before settling down into a string of evenly spaced single bubbles.
The researchers say the bubble pattern follows a sequence known as "period-adding route", which is similar to patterns seen in rhythmic processes in physiology and ocean motion.
They developed a mathematical model that shows the variations in bubble patterns depends on factors such as champagne temperature and the concentration of dissolved CO2.
It also depends on the way the bubbles form on the side of the glass, particularly the size they are when they break away.
"The important thing about this paper is that it leads to an understanding of how to control bubbles, which is very important for wine-making," says Professor John Ralston, a physical chemist from the University of South Australia.
Ralston also says the general science behind the work is relevant to a broad range of industrial processes that involve bubbles.
These include the manufacture of cosmetics, pharmaceuticals as well as mineral, recycling and water purification processes.
The research could also help in understanding nitrogen bubbles that form in the blood of surfacing divers that can cause decompression sickness.
And it could help to explain events like the explosive release of CO2 from Cameroon's Lake Nyos that killed over 1800 people in 1986.
Getting the best "mousse"
Adelaide-based Australian winemaker Brian Croser, who has been making "sparkling wine the champagne way" since 1984, and whose company has a partnership with Bollinger in France, welcomes the research.
He says bubbles are central to the pleasure of watching and drinking a glass of champagne. For one, they help to explode the aroma of fruit and yeast just beneath your nose as you're drinking.
One of the holy grails of champagne makers is to make sure bubbles are small and rise slowly through the drink. This ensures the champagne retains its fizz for longer and gives a smoother sensation in the mouth, known as mousse.
"A point of difference between sparkling wine and table wine is the presence of CO2 and you need it to behave properly," says Croser.
He says the new research will help winemakers to control bubble behaviour by manipulating the amount of CO2 in their wine.
Don't clean those champagne glasses too well
Champagne bubbles can only form if the glass is slightly dirty, for example if there are small fibres left behind by a tea towel, says Croser.
He says glasses cleaned to within an inch of their life in dishwashers will have no "nucleation sites" from which bubbles form and, sadly, champagne poured in them will have no bubbles.
So how best to clean one's champagne glasses?
"That's the subject of the next paper," he says.