The secret to making sparkling wine is knowing what chemical reactions happen during the winemaking process.
The fermentation reaction process produces carbon dioxide as a natural byproduct.
Fermentation occurs when yeast combines with sugar to create alcohol and develop carbonation by harnessing the natural carbon dioxide that builds up.
Making sparkling wine is all about capturing CO2.
There are two methods of forcing CO2 back into the wine:
The Charmat Method
The Champenois Method
The Charmat method, used to make Prosecco in Italy, is when we ferment the wine in a pressurized tank. The CO2 is trapped and naturally forced into the wine by the intense build-up of pressure. An isobaric bottling line then bottles the wine. (Isobaric means it can withstand bottling under pressure.)
The other method is called the Champenois method, from France, which forces the carbonation of CO2 into the wine directly inside a bottle. It’s a more complex and time-consuming system than doing this in a steel tank.
This method bottles the wine early to trap the CO2 inside the bottle during the fermentation process of the residual sugar. The highly pressurized bottle must be thick glass strong enough to withstand the massive build-up of CO2 pressure.
The bottle is frozen upside down, so the neck of the bottle, which has the yeast residue from fermentation, freezes before opening to remove the ‘ice cork’ and yeast debris. The bottle is topped up with finished sparkling wine and recorked.
And that is how we make sparkling wine.