What causes the bubbles in Champagne?

14th July 2020

Where do Champagne bubbles come from

Champagne for many of us is all about the fizz, the pop, the effervescence or quite simply the bubbles! What sets Champagne and many other sparkling wines apart is, of course, the lively character thanks to the appearance of the bubbles – I am sure you are familiar with letting Champagne go flat and how different and less exciting it tastes?

“There are approximately 49 million bubbles in a standard sized bottle of Champagne.” Champagne facts about bubbles

A question that I get asked, especially when I am pouring a glass of something bubbly for friends, is ‘Why do some wines have bubbles and others do not?“. A very fair question and one that isn’t too difficult to answer and the origin of which lies in the production methods.

In simple terms, all wines can / will produce bubbles with the difference between still wines and fizzy wines being that any bubbles are released for still wine (and the fermentation part of the winemaking process will have been stopped in time) and are contained for fizzy wine (in the second fermentation process). Some sparkling wines produce their own bubbles depending on how they are made in the bottles, others have the bubbles appear in the tank (Charmat method) and the bottles have bubbly wine added directly.

The first fermentation makes the wine whereas the second fermentation makes the bubbles.

Champagne bottles stored in Epernay

Champagne bottles stored in Epernay


Champagne method

Champagne is made in a way which is called the traditional method, also known as the Champagne method / méthode Champenoise. This means that the second fermentation takes place in the bottle meaning that carbon dioxide is made naturally during this second fermentation period and this all takes place inside the bottle – The yeast eats up the sugar molecules and leaves carbon dioxide (and ethonal) in its place.

How exactly does the glass of Champagne still produce bubbles after it has been poured then? Well that is down to the dissolved gas which, after being depressurised following bottle opening, sees tiny pockets gather / attract together to form bubbles which of course rise in the liquid looking to disappear so that the equilibrium is restored.

“Since the bottle is capped the bubbles produced by this second fermentation cannot escape and are therefore absorbed into the wine. Bingo, sparkling wine!” Colin Harkness ‘There’s more than one way to Fizz a Wine!

Eventually, the bubbles will die down once all the carbon dioxide has been released thus we will have flat Champagne – Any Champagne expert will tell you that at this point it is certainly not worth drinking and flavours and aromas will be lost (though some will recommend that you use it for cooking).

Fizzy drinks including Prosecco, Cola and Lemonade will have the same formation of bubbles thanks to carbon dioxide escaping the liquid.

Christopher Walkey

Co-founder of Glass of Bubbly. Journalist and author focused on Champagne & Sparkling Wines and pairing them with foods.