There are two major methods of carbonating wine among commercial producers.
The Charmat process involves a bulk secondary fermentation in a sealed vessel, carbonating the wine; the carbonated wine is then racked under pressure into bottles without disturbing the yeast. Because this method is used for many traditional Italian sparkling wines, it is sometimes also called Metodo Italiano.
By contrast, in the older MÃ©thode champenoise used to carbonate Champagne and many other styles of wine and mead, and even some styles of beer, notably lambic. In this process the wine is carbonated in the bottle through a secondary fermentation; the bottles inverted so that the yeast collects in the neck; the neck of the bottle is frozen to create a plug of ice encapsulating the yeast; and the temporary cap is removed, allowing the existing pressure to force the ice-yeast plug out through the neck of the bottle, which is then recorked to preserve the remaining carbonation.
Home producers can also use traditional force carbonation methods common in beer making; however, some vintners feel that the carbonation produced by this method is not of as high a quality.