Researchers at the thermomechanics department of GRESPI (the Group for Research in Engineering Science) at the University of Reims Champagne-Ardenne are using thermography to study the best way to pour champagne.
The researchers tested how the way champagne is poured influences the loss of CO2, which has been proven to contain most of the champagne's aroma. In fact, there are up to 30 times more flavour-enhancing chemicals in the bubbles than in the rest of the drink.
The research found that, firstly, serving champagne chilled helps to contain the CO2 and thus the champagne's flavour. Secondly, the classic pouring technique for champagne, holding the glass vertically and allowing the champagne to hit the bottom of the flute, was found to be not as effective at retaining CO2 compared to the 'beer-like' pouring method (holding the glass aslant and letting the liquid to flow down the sides).
The diffusion of CO2 during the pouring process was filmed with a Flir SC7000 thermal camera, which provided the researchers with a further scientific validation of their experimentation.
Visualising the CO2 emission wasn’t as easy as just pointing a thermal camera at the champagne glass. GRESPI researcher Hervé Pron explained: 'The CO2 absorptions observable by thermal cameras are quite weak because this gas molecule has only a strong absorption peak in the detector bandwidth at 4.245μm. So we needed to look at that specific bandwidth.'
To do that the group used an external band-pass filter. 'The camera operates at a bandwidth of 3 to 5μm. To look at the thermal emission from the escaping CO2 we acquired an external band-pass filter that was centred on the CO2 emission peak and only allows infrared that has the bandwidth of the particular wavelength region we need to pass,' Pron continued.
Pron was pleased with the camera's performance: 'We needed a thermal camera that's easy to calibrate, very accurate, lightweight, easy to use and has a high resolution. This camera delivered just that. We could see enough detail, without too much background interference, or "noise".'
In recent years, glassmakers have proposed to consumers a new generation of champagne tasting glasses, specially designed, with a well controlled CO2 release during the entire tasting process. This has been the driving force behind the rapidly growing interest behind gaining a better understanding and depicting each and every parameter involved in the release of gaseous CO2 from glasses poured with champagne or sparkling wine.
The next step in champagne research is to produce a complete mathematical model of CO2 dissipation during the pouring process which includes the multiple ways of CO2 discharge during the pouring process. This model is under construction, according to Guillaume Polidori, director of the thermomechanics department of GRESPI.