Sparkling wine contains carbon dioxide coming from the fermentation. It is dissolved in the
wine thanks to a hermetic closure of the bottle and will be released when opening the
bottle. Here are 4 methods to produce sparkling wines:
1. The traditional method
This is the most appreciated method in terms of quality but also the most expensive one.
It starts with a base wine (not sparkling) to which sugar is added and the wine is bottled.
The second fermentation can now start in the bottle and the process creates CO2 which is
trapped inside the bottle, carbonating the wine. The yeast dies and remain in the bottle.
Wines are aged on their lees. The winemaker will put the bottles upside down (riddling) in
order to remove the sediments from the bottle (disgorging). Finally, the last stage is the
« dosage » that consist of adding some wine and sugar to fill the bottle.
This is the method used by most good quality sparkling wines including Champagne and
Cava. Note that Champagne requires a minimum of 15 months of aging and Cava requires a
minimum of 9 months of aging.
2. The Ancestral method
This method is very technical and because it uses the « spontaneous fermentation ». This
method uses icy temperatures to pause the fermentation mid-way for a period of months
and then wines are bottled and the fermentation finishes, trapping the CO2 in the bottle.
When the desired level of CO2 is reached, wines are chilled again, riddled and disgorged just
like the traditional method, but no sugar is added.
3. The Tank method
In this method, base wines are added together with the sugar and yeast mixture (tirage)
into a large tank. As the wine has a second fermentation, the CO2 released from the
fermentation causes the tank to pressurize. Wines are then filtered, dosed and bottled
without aging. The main difference with the traditional method is that the 2nd fermentation
is not made in the bottle. This is the main method used to produce Prosecco.
4. The Transfer method
This method is similar to the Traditional method as the 2nd fermentation takes place in the
bottle as well but at the end of this 2nd fermentation bottles are emptied into a pressurized
tank and sent through pressurized filters to remove the lees. Finally, the wines are re-bottled.