It’s hard to believe, but effervescence in wine was not always considered a good thing. For centuries, Old World winemakers in cool regions struggled with bottles that would re-ferment when hot, which would create unintentional bubbles. But during the 17th century, French winemakers began to harness the process and developed various methods to produce sparkling wine. Today, there’s an array of bubbles, from Champagne to Cava, all made with slightly different methods.
Many of the world’s best sparkling wines are made by the méthode traditionelle, or traditional method, where still wine is bottled before additional yeast and sugar are added. Under a crown cap, typically, the yeast ferments sugar into alcohol until dry, which gives off CO2.
The sparkling wine then ages on the dead yeast, called lees, which adds notes of brioche and textural richness. The bottle goes through a process known as riddling where the bottle is frequently turned and repositioned at severe angles until all the sediment rests in the neck. The wine is disgorged to remove the lees sediment. Dosage, a blend of sugar and wine to add sweetness, is added typically before the wine receives its finishing cork.
This traditional method is most associated with the wines of the Champagne region, where the process is legally protected as méthode Champenoise. Its cool climate creates searing acidity in dry, low-alcohol base wine, which is made more palatable by secondary fermentation in bottle.
Though it’s recently come back into fashion, the ancestral method of sparkling wine production is thought to predate the traditional method. Rather than induce secondary fermentation, the méthode ancestrale bottles the wine before it has completed its first fermentation.
The moment of bottling is crucial. There must be enough sugar in the wine to build pressure and create bubbles, but not so much that the bottle explodes. Because of this, many méthode ancestrale wines have softer bubbles, and there may be some residual sugar. There’s no requirement to disgorge the wine, so many méthode ancestrale wines contain sediment or appear cloudy.
While méthode ancestrale has been integrated into the legislation of regions like Bugey Cerdon for decades and practiced in Limoux for centuries, it has gained momentum via the pétillant-naturels of the natural wine movement.
The tank method, also known as the Charmat method, was developed around the turn of the 20th century. It carries out secondary fermentation in a pressurized tank, rather than in bottle. Yeast and sugar are added to the tank, and the wine is chilled usually to stop fermentation.
The wine is then filtered and bottled under pressure without any significant contact with its lees, which makes this method popular among producers and regions that want to emphasize fresh fruit aromas and flavours.
Perhaps most emblematic of the tank method is Prosecco, which began to use it in earnest to make sparkling wines in the 1960s and ’70s. The method allows the Italian region’s delicate, semi-aromatic Glera grape, formerly known as Prosecco, to be made into a clean, youthful wine.