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The Physics of Festive Fizz

With the holidays fast approaching, many of us are looking forward to drinking a glass or two of Champagne and other sparkling wines.  After all, these are perfect celebratory drinks – but what does physics have to say about how they might best be served?

1. Gently Pour into an Inclined Glass

The traditional way of pouring Champagne and sparkling wines is into an upright glass, which produces a frothy head. Sommeliers may love the drama that this produces, but a great deal of CO2 is lost in the process. This is bad news because such a dramatic loss of dissolved CO2 will (1) result in a glass which is less vivacious and (2) contain lesser amounts of volatile organic compounds (VOCs) which are carried in bubbles.

Champagne-Pour-Angle

Research by Gérard Liger-Belair and colleagues at the Université de Reims has shown that by pouring into an inclined glass – much as one would pour a beer – the wine can contain up to twice as much dissolved CO2.  And that means a longer-lasting bubble stream and more intense aromas.

2. Use Flutes Not Coupes

Coupes are the traditional glass of choice for serving Champagne and sparkling wine, but they are to be avoided, even those that are modelled on Kate Moss’s left breast.  There are two main reasons for this.  In a coupe, the sparkling wine will have a much greater surface area in contact with the air, compared to a flute.  Since much CO2 is lost by diffusion at this interface the flute will naturally retain CO2 for longer.

Champagne-VortexSecondly, the differing shape of coupes and flutes result in differing patterns of convection and surface bubble burst.  These bubbles are not merely aesthetic but carry with them volatile organic compounds which are a characteristic of that particular sparkling wine. With a flute the vortex zone covers the entire width of the glass and VOCs are contained within a relatively small volume. By contrast with a coupe, the vortex zone covers only about half of the wine surface.  This results in a doughnut shape adjacent to the rim with far fewer bubbles and VOCs.

3. Serve Chilled but not Cold

The temperature of sparkling wine affects its viscosity and the rate at which CO2 molecules are able to diffuse.  This means that the cooler the sparkling wine the longer it will retain its dissolved CO2.  Just as a rapid loss producing a frothy head is undesireable, so also is too slow a loss.  The latter with a sparse flow of bubbles, is aesthetically less apealing and also has a reduced flow of VOCs.  Experience of tasters suggests that 8°-10°C is a good temperature at which to serve the majority of Champages and sparkling wines.

 

References

Beaumont, F et al. (2013) Temperature Dependence of Ascending Bubble-Driven Flow Patterns Found in Champagne Glasses as Determined Through Numerical Modelling.  Advances in Mechanical Engineering, 10pp

Liger-Belair, G. (2013) Uncorked: The Science of Champagne. 216 pp

Liger-Belair, G. et al. (2010) On the Losses of Dissolved CO2 during Champagne Serving. J. Agric. Food Chem. v 58, p. 8768–8775

Liger-Belair, G et al. (2012) Monitoring Gaseous CO2 and Ethanol above Champagne Glasses: Flute versus Coupe, and the Role of Temperature. PLoS one

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