Sparkling wines

These wines are pressurised with the CO2 that is generated during the fermentation process, and kept inside the wine by placing an airtight seal on the bottle. European regulations have laid out a coding system for these wines depending on the volume of gas and the pressure exerted. A semi-sparkling wine contains 2 to 4 g of CO2 per liter while a sparkling wine has a gas content of more than 4.5 g per liter.