Sparkling wine production methods
Most quality sparkling wines are the result of two fermentations. One is to turn the grape juice into still wine (this is called base wine) and the subsequent one is to turn the base wine into sparkling wine. The winemaker instigates the second fermentation by adding yeast and sugar to the base wine. Additional yeasts convert the sugar into alcohol and carbon dioxide (CO2) bubbles.
Carbon dioxide is a natural by-product of this conversion. When fermentation takes place in a closed container that does not let it vent, the dioxide is trapped in the wine in the form of bubbles.
During the second fermentation, the slower and longer the vinification process, the more complex and expensive the sparkling wine will become.
Some stay ten years in the cellars others are produced in a few months. Slow wines can cost upwards of $100 a bottle while at the other end of the spectrum they can be quite cheap.
Although there are many variations, most quality sparkling wines are produced mainly in two ways. Second fermentation in the tank or second fermentation in the bottle.
The fastest and cheapest way to produce sparkling wine involves carrying out the second fermentation in large closed tanks. This method is called the tank method, cuve–close (meaning closed tank in French), or Charmat method (after the Frenchman Eugene Charmat, who championed this process).
Sparkling wines produced using the Charmat method are usually more economical. This is because they are usually made in large quantities and are ready for sale very quickly after harvest. The whole process can take just a few weeks. Also, the grapes used in this method (Chenin Blanc, for example) are usually much cheaper than the Pinot Noir and Chardonnay typically used for the traditional Champagne method.