When people think of sparkling wine more often than not their mind immediately goes to champagne. Sometimes the terms are even interchangeable for them, asking for a glass of champagne refers to anything with bubbles. But champagne is particular, not only is it produced through a very specific method, méthode champenoise, and it can only be called Champagne if it comes from Champagne France. Today though we are going to put aside Champagne (don’t worry, that’s coming later) and focus on the other methods of making sparkling wines. Because even though Champagne is the most famous of the bunch there are a wide variety of sparkling wines produced around the world.
Sparkling wine is wine that contains dissolved carbon dioxide, which is released from the wine when the bottle is opened. The amount of carbon dioxide present in the wine determines a range of bubbles that can be anywhere from just slightly fizzy to intensely frothy. Any sparkling wine starts the same way as any other wine, as a still base wine. Once this base wine has been produced there are a variety of different methods used to produce the wine’s signature bubbles. These methods include, of course, method champanoise, the Charmat method, the transfer method, and force carbonation.
The Charmat method, aside from the champagne method, is the most widely practiced. This method is occasionally also called the tank method. As with all sparkling wines double fermentation takes place, the first fermentation to make the still base wine and the second fermentation to create the carbonation. In the Charmat method this second fermentation takes place in large, pressurized stainless steel tanks. The still base wine is added to these tanks along with a mixture of sugar and yeast to begin the second fermentation. As the yeast converts the sugar to alcohol the by product is carbon dioxide, but because this process is taking place in a closed tank that gas has no where to go to escape so it is eventually dissolved into the wine, creating the bubbles. Once this secondary fermentation is complete the wine is also bottled under pressure to maintain the carbonation level in the wine. Because this entire process takes place in a large tank the wine doesn’t come into much contact with the yeast and therefore wine produced in this method showcases a purer expression of fruit. This method also tends to produce larger bubbles which can dissipate quickly. Wines made in this method include Prosecco, Asti, Moscato d’Asti, German Sket, and many American sparkling wines.
Another method used to produce sparkling wine is known as the transfer method, though it is no longer as commonplace as it once was. In this method the still base wine is placed in individual bottles with the sugar and yeast mixture for the secondary fermentation. The wines are allowed to age for a little while in the bottles after the second fermentation is complete, meaning that they get a little more direct contact with the yeast cells than wines made from the Charmat method giving these wines a slightly more yeasty character. After a small amount of bottle aging the bottles are then emptied into pressurized tanks. This means that the wine from all the individual bottles are blended together and clarified under pressure in the tanks and then re-bottled.
And finally there is forced carbonation, which is by far the least desirable means of producing a sparkling wine. During this method carbonation is not created as a natural by product of the yeast but instead the base wine is put into large stainless steel tanks and carbon dioxide gas is pumped into the wine under pressure. Typically only lower quality sparkling wines are produced in this manner.