Many of you opened some bubbly over the holidays but have you ever wondered how it’s made? The process is laborious, especially for Champagne or sparkling wines made in the traditional method.
When grape juice is fermented and becomes wine, carbon dioxide is created and allowed to disperse. If fermentation takes place in a sealed container (i.e. a bottle) and the gas is not allowed to escape, pressure builds up and the wine absorbs the carbon dioxide where it stays dissolved until released resulting in bubbles in your glass. The pressure in sparkling wine is typically 70 – 90 psi or about the tire pressure of a double decker bus! This pressure demands a thick glass bottle and a cork that becomes mushroom shaped (due to pressure) with a wire cage on it.
Champagne starts with base wine: a still wine utilizing white wine grapes that have high acid and low alcohol. The winemaker adds yeast and sugar to this base wine to initiate a second fermentation in the bottle. The bottle is immediately capped and the wine is aged on its lees (dead yeast cells and solids). Some of the lees dissolve and are absorbed into the wine. After aging, the sediment is removed. The wine is quickly topped off with base wine and sugar and resealed for sale. Many new world and European producers use this traditional method but are not allowed to label as Champagne since the wine is not from the Champagne region in France. Spanish Cava is produced using the traditional method. Italian Prosecco is produced using a method called Charmat or Tank method.
Once opened, a bottle of champagne has approximately 56 million bubbles. Finer wine will have smaller bubbles due to longer aging and cooler aging cellar temperatures.
Something to ponder the next time you pop a cork and share some bubbly with friends.