Pouring and CO2 loss

The experiment

Researchers in Reims poured champagne holding 11.4 g/L of dissolved CO2 into flutes in two ways and measured what was left.¹ The "champagne-like" pour goes straight down into the middle of an upright flute and builds a tall head of foam. The "beer-like" pour runs gently down the wall of a tilted glass. They repeated both at three temperatures.

Results

All values from Liger-Belair et al., J. Agric. Food Chem. 2010.¹ In gas volume, the vertical pour at 4 °C released about 166 cm3 of CO2, the tilted pour about 88 cm3.¹

At 12 °C the vertical pour released about 182 cm3 of gas and the tilted pour about 110 cm3; at 18 °C the figures were about 221 and 204 cm3.¹

Two patterns stand out. The tilted pour kept more CO2 at every temperature. And losses grew with temperature for both methods, which the authors link mainly to how fast CO2 diffuses and to the viscosity of the wine. At 18 °C the advantage of the tilted pour almost disappeared.¹

In the glass after pouring

The losses continue after the pour. In a 2012 study with a bottle at 12 °C, champagne in a flute held 7.4 g/L just after pouring and about 3 g/L after 15 minutes.² The shape of the glass also changes how that gas leaves: see flute or coupe.

Why it matters

The CO2 left in the wine after the pour is the reserve that feeds the bubbles in the glass and the gas that rises to the nose. Every gram per litre lost at the pour is gone from that reserve.

In practice

The Comité Champagne advises pouring in two stages, slowly and steadily.³ The laboratory data add two points: tilt the glass if you want to keep the fizz, and serve the wine cold. Practical steps are on how to pour and serving temperature.