Sparkling wines

Sparkling wines are the ones with significant levels of carbon dioxide in them, making them fizzy. European countries legally reserve the "champagne" term for products exclusively produced in the Champagne region of France. Sparkling wines are usually either white or rosé, but there are examples of red sparkling wines such as the Italian Lambrusco, Australian sparkling Shiraz.

There are mainly five methods of wine making: the Traditional Method (or Champenoise), the Tank Method (or Charmat), the Asti Method, the Transfer Method, and the Carbonation.

The traditional method is the process used in the Champagne region of France to produce Champagne, where the second fermentation of the wine takes place in the bottle. It is also the method used in various French regions to produce sparkling wines (not called “Champagne”) and in Italy to produce Franciacorta. The method is known as the méthode champenoise, but the Champagne producers have successfully lobbied the European Union to restrict the use of that term within the EU only to wines produced in Champagne. Thus, wines from elsewhere cannot use the term "méthode champenoise" on products sold in the European Union it is used the term "traditional method" (méthode traditionnelle) or metodo tradizionale in Italy. South African wines from the Western Cape are labelled with the term Methode Cap Classique. 

The tank method is used for most of the inexpensive sparkling wines. It is also known as the Charmat method or sometimes referred to as "cuve close". In this technique, the second fermentation takes place in a sealed tank rather than in a bottle. Dry base wine is placed, together with sugar, yeast, nutrients and a clarify agent, in the tank and following the second fermentation the resulting sediment is removed by filtration, before bottling under pressure.

The main advantage of this method is that it reduces considerably the costs. The method is particularly useful for fruity styles of sparkling wines such as Prosecco and with aromatic varieties such as Riesling or Muscat.

The Asti method is different from other methods used for most sparkling wines as it does not involve the production of a still dry wine. The must is stored at close to freezing point until it is need. When it is required the must is warmed and the fermentation takes place in pressurised tanks. Carbon dioxide  is allowed to escape until the alcohol level reaches 6%. At this point the carbon dioxide is retained. The fermentation is stopped by chill filtration and the wine is bottled for immediate sale. A variation of the Asti method is used for the Moscato d'Asti.

The transfer method attempts to gain the advantages of a second  fermentation in the bottle without the disadvantages and expense of the complicated process of riddling and disgorgement required by the traditional method. Up to the process of riddling the process is the same as in the traditional method. In the transfer method, however, the entire contents of the bottle are disgorged into a tank under pressure, filtered in bulk and then rebottled into a fresh bottle.

This method is mainly used in the New World and a version of it is used in Champagne for formats other than half bottles, bottles, magnums and jeroboams.

Carbonation is the the cheapest method of all and it is not considered to be a method capable of producing quality wines. This is the only method where the carbon dioxide, produced as part of an alcoholic fermentation, is not used to make a wine sparkling. Instead of it, the carbon dioxide is injected into the wine. it puts bubbles into the wine, but does not otherwise alter it.