Authored by Sandra Parker in Food and Cooking
Published on 09-09-2009

Sparkling wine is merely still wine with the addition of carbon dioxide.  The carbon dioxide adds the familiar fizzy sensation you experience when consuming the wine.  This carbon dioxide can occur naturally through the fermentation process, or can be added during the manufacturing process through injection.  Champagne is a type of sparkling wine.

Effervescence has been seen throughout the history of winemaking and can be traced back all the way to the ancient Romans and Greeks.  Wine that came from the Champagne region tended to have a light sparkle due to the natural fermentation process the wine underwent. This was regarded as a flaw by winemakers. 

To encourage the natural carbon dioxide producing characteristics of fermentation, the grapes used to make sparkling wine are generally plucked early in season when the levels of acid are still high in the fruit.  Great care is taken to harvest the grapes by hand to prevent damage to the fruit, causing premature fermentation to take place. 

The  press house is usually located in very close proximity to the vineyard so that immediate processing can take place.  Careful consideration is taken so that the pressed grapes do not come into contact with skin to avoid adding substances that may alter the fermentation process.

Primary fermentation resembles that of still wine, though the choice of yeast may differ.  Depending on the flavor and color of the wine, sparkling wine may undergo a process called malolactic fermentation, though this process is not necessary.  After the base wines have been initially fermented they are blended together.  Almost all sparkling wines are a blend of several grape varieties, giving them a unique taste and texture from still wines which are usually comprised of a single grape variety.

It is the secondary fermentation process that separates sparkling wines from still wines.  During the secondary fermentation process, the base wine mixture is added to a fresh yeast and sugar mixture in the bottle that the wine will be sold out of.  The dead yeast cells will be removed through a process called disgorgement and the dissolved carbon dioxide will be retained in the liquid.  More wine and sugar will be added to adjust the taste of the wine where it will then be bottled and sent to market.  Other sparkling wines will forgo the disgorgement process, opting to leave the yeast cells in the wine as sediment. 

In a carbon dioxide injection process, fermentation will occur in a stainless steel vat that is pressurized.  The yeast and sugar are added under high heat, high-pressure conditions.  The wine is cooled, and then clarified.  Instead of subjecting the wine to a secondary fermentation process, the carbon dioxide is injected into the liquid and is bottled.  This process is generally reserved for only the least expensive brands of sparkling wines.