Wines from the Champagne region were still but susceptible to variations in temperature and the cold winters would stop the fermentation process, leaving some residual sugar and yeast in the wine. Bottling at this point meant that any rise in temperature would cause the fermentation process to start again, producing carbon dioxide and a build-up of pressure in the bottle.
Stoppers would fly off or bottles explode, the shards of glass often hitting other bottles and causing a chain reaction of exploding bottles and the occasional injury to the unwary vintner. Not for nothing did the French call this wine vin du diable, the devil’s wine, or saute-bouchon, jumping cap. Gassy, bubbly wine was seen as a grave imperfection and much effort was expended to eliminate this dangerous side-effect of the fermentation process.
Once the Champagne wine had arrived in England and the temperature had risen, it too became fizzy when opened, producing those distinctive bubbles that we now come to associate with the drink. However, by this time the English had made great strides in improving wine storage technology.
The innovations of Sir Kenelm Digby and the use of coal-fired ovens produced glass which proved to be stronger and more durable than the wood-fired French glass, providing wine bottles capable of storing wines under high internal pressure. The almost contemporaneous introduction of cork as a means of capping a bottle resulted in a tighter and more secure fit.
For the English, these innovations meant that spontaneously popping wine corks and exploding bottles were less of problem. Indeed, the bubbles released when opening the wines, far from being galling as they were to the French, were seen as a rather pleasing novelty. They rather tickled their fancy, and their noses, you might say.
The phenomenon was so intriguing that the English scientist, Christopher Merret, took a closer look, presenting his findings in a paper to the Royal Society on December 17, 1662 entitled Some Observations concerning the Ordering of Wines. He described how winemakers added sugar and molasses to encourage a secondary fermentation which resulted in a brisk (frothy) and sparkling drink. What Merret was describing later became known as the méthode champenoise. Any wine, he declared, could be made to sparkle if sugar was added prior to bottling.
The taste for “brisk champagne”, as Samuel Butler dubbed it in Hudibras (line 570)) in 1663, grew in popularity and other European courts took up the craze. Clearly, wine merchants, and English at that, were adding sugar, albeit in a rather hit or miss fashion, well before Dom Pérignon began “drinking the stars”.
The French Benedictine monk’s major contribution to champagne production, after spending years trying to eliminate bubbles, was to establish ways of increasing carbonation. It was not until the 1830s, though, that a pharmacist, André François, produced formulae showing precisely how much sugar was needed to make a wine sparkle without producing so much pressure that the bottle would shatter.
In champagne production, the flat base wine from the first fermentation is bottled with a mix of yeast and sugar. As the yeast consumes the sugar, the wine ferments again, producing alcohol and carbon dioxide. A finished champagne bottle is under around five to six atmospheres of pressure and when the cork is released, the carbon dioxide rushes out in the form of tiny bubbles. To regain its equilibrium the liquid must release six times its own volume in gas, of which around 80 percent of the carbon dioxide simply diffuses into the air. The remaining 20%, still in bubble form, remains in the bottle to be transferred into a glass when poured. When they pop, they produce that intriguing and intensely pleasurable sensation on our nose and mouth.
Contrary to popular opinion, there are no bubbles inside a bottle of champagne; they are the result of the reaction caused by releasing the cork. More pertinent is how many end up in our glass and this is where we are indebted to the research of Gérard Liger-Belair, from the Université de Reims Champagne-Ardenne.
The ingenious Liger-Belair built a theoretical model to examine the factors that might have an impact on the final figure, including how much carbon dioxide escaped from the glass without forming bubbles, how bubbles changed size over time, as well as considering the number of gas pockets trapped between particles, bubble nucleation sites, and the pressure of the bottle at room temperature. Adding a splash of ascending bubble dynamics to the mix, he pressed go.
His model led Liger-Belair to conclude that “one million bubbles seem[ed] a reasonable approximation for the whole number of bubbles likely to form if you resist drinking champagne from your flute”, far fewer than the fifteen million that some champagne manufacturers claim. Serving champagne at a slightly warmer temperature than normal and tilting the glass while pouring will increase the amount of fizz. `
The shape of the glass also effects the number of bubbles produced. Tall, thin glasses produce a fast stream of bubbles which dissipate quickly while wide, shallow glasses produce bubbles at a slower rate and they linger longer, filling the air with the drink’s distinctive and inviting aroma.
There is more to champagne than hits the eye, it seems.