Sparkling wines are made by every wine-producing country in the world. The carbon dioxide which creates the bubbles in the wine is a natural by-product of fermentation.
If the wine-maker intends his product to be sparkling, he traps the gas in the wine. There it remains dissolved until the pressure is released, when it rapidly makes its way to the surface in the form of tiny bubbles.
There are various ways of capturing fizz in a wine. The best is the methode champenoise, used not only in Champagne but throughout the wine-making world. The way in which the gas is trapped can vary, from a highly skilled, labour-intensive science to a heavy-handed, mass-produced routine, as can the quality of the base wine itself. The best base wines for sparkling wine are those with high acidity and little character. That the soil (chalk) and climate (cool) of Champagne are ideally suited to producing wines of this type is a major facto in explaining Champagne’s pre-eminence among sparkling wines.
The Champagne Method (AKA methode classique or traditionelle)
Used for : Champagne; Cava; Cremant de Loire, de Bourgogne and d’Alsace; Blanquette de Limoux; quality New-World sparkling wines; Italian “Metodo Classico”; quality German Sekt.
After the blending of the base wines, a solution of wine and sugar is added, along with specially cultured yeasts, to provoke a secondary fermentation. The bottles are then stacked on their sides in a cool cellar and left for the second fermentation slowly to run its course.
Traditionally, the bottles were then placed, neck first, into specially designed sloping racks called pupitres, where skilled remueurs would, over the course of a few weeks, daily shake, rotate and tilt the bottle slightly to shift the sediment down so that it rested on the cork. Nowadays this job is generally done – many say – just as effectively by machine called giropalettes.
Finally the necks of the bottles are chilled, freezing the sediment into a solid plug. When the corks are removed, the plug pops out under the pressure of the carbon dioxide in the bottle. The wine remaining in the bottle is then topped up with more of the same wine and a little liquid sugar, known as the dosage, before being corked with the traditional Champagne cork tied down with wire.
The Transfer Method
Used for : more run-of-the-mill European wines such as Kriter from France; some New-World fizz.
This is essentially a “second-best” cross between the Champagne and cuve close (see below) methods. The second fermentation takes place in the bottle and the wine is transferred under pressure to tanks for dosage, filtering and re-bottling.
The Cuve Close, Charmat or Tank Method
Used for : basic French sparklers; all but the best German Sekt; most Asti; Spanish “Granvas” fizz.
Invented by the Frenchman Charmat, this method can make tolerable sparkling wine – ideal, perhaps, for mixing a Buck’s Fizz. The base wine is run into huge stainless steel tanks where secondary fermentation takes place at a controlled temperature, followed by dosage, filtering and bottling.