Where Do the Bubbles in Champagne Come From?

CHAMPAGNE: The Steps of Production

Champagne requires multiple stages of production and often the steps are identical to that of a still wine: harvesting, fermentation, vatting, blending... What differentiates still wine from Champagne and other sparkling wines is a second fermentation in the bottle. The yeasts transform the sugar into carbon dioxide, which remains trapped in the bottle and therefore dissolves in the wine.

- Champagne is vinified in the same way as white wine:

Alcoholic fermentation takes place, the yeast transforms the natural sugar in the grapes into carbon dioxide, which evaporates, next up is the pressing. The wine is dry and is called " still wine ", it does not sparkle.

- With an additional step, the second fermentation in the bottle:

After the different blends are finished, the resulting still wine obtained is bottled and so called liqueur de tirage (yeast, wine and sugar solution) is added in order to create secondary fermentation in bottle. In the bottle, the yeast converts the sugar into alcohol and carbon dioxide and the wine becomes effervescent. The bottles are placed upside down and every day for several weeks, each bottle is turned a quarter turn to slide the deposit of fermentation towards the neck. This is called riddling, which is followed by 'disgorging' the cork to remove this deposit that is expelled by pressure.

Then a liqueur d'expedition (a wine and cane sugar solution) is added to make up for the quantity expelled before the final corking. Well dosed, this liqueur d'expedition influences the intensity of the foam formation and the desired sweetness: from Champagne Extra Brut to Champagne Doux (driest to sweetest).

WHAT ELSE IS THERE TO KNOW ABOUT BUBBLES?

The Champagne bubbles are bubbles of carbon dioxide directly produced during alcoholic fermentation. Taking place in the closed bottle, the CO2 is then blocked under the cork. The pressure of the bottle increases as the gas accumulates. That's why when you open the bottle the cork pops!

The apparition of bubbles:

When the bottle is closed the bubbles are hardly visible, it is once the bubbles are in the glass that they rise to the surface to return to their original gaseous state. They are then charged with aromas which are then released at the surface when the bubble explodes.

The creation of bubbles:

The bubbles in a glass of Champagne are induced by the presence of impurities. When the Champagne is poured, its carbon dioxide gas pockets interact with these impurities to form their bubble and rise. A glass with a smooth and completely clean wall then does not allow the champagne to deliver its finer bubbles. It is therefore advisable not to wash your glasses with washing-up liquid but simply rinse them with very hot water. This method leaves some impurities on the glass, which will guarantee that the bubbles of your Champagne will express themselves better next time round.

The rise of the bubbles to the top of the glass:

When a bubble forms on an impurity, it remains stuck to the glass wall until it is large enough to start its journey to the surface. As the bubble makes its way to the surface of the glass, it gradually becomes charged with carbon dioxide. It is this gas that allows the bubble to grow. When your glass is already well aired, the Champagne is depleted of gas. As a result, the bubbles become finer and finer.

The size of the bubble is an indicator of the amount of gas present in the bottle. It is not an indicator of the quality of the Champagne. You can end up with about 2 million bubbles in your glass of Champagne!