We don’t know about you, but there is something truly magical about opening a bottle of sparkling wine at a special occasion. The pop of the cork and that effervescent tingle of the wine on the palate are one of life’s greatest pleasures. But what gives these wines their sparkle?
There are six major methods by which sparkling wines are produced, however it is the traditional method or ‘méthode traditionnelle’ that is responsible for the finest example of sparkling wine, Champagne.
In 2015, the traditional method of sparkling winemaking was awarded a UNESCO heritage in Champagne. And for good reason; it is arguably the most appreciated method for sparkling wine production in terms of quality, and at the same time it is also the costliest in terms of production. The most important aspect of this process is the transformation from a still to a sparkling wine, which occurs entirely inside the bottle. Learn more about the steps of this age-old process below.
1. Base wine
To create a sparkling wine you need to start with a still wine. Grapes are handpicked - usually a little earlier to preserve acidity - and fermented to a dry wine, before the winemaker blends them to the wine’s final cuvee. Sometimes base wines from previous years are used to help create a ‘house style’. This ensures stylistic consistency year on year, and is indicated as non-vintage (NV) sparkling wines.
This step is where the base wine really begins its transformation into a sparkling wine. Once the blend of the base wines is complete, a mixture of wine, yeast and sugars called the liqueur de tirage are added to the cuvee to initiate a second fermentation. The wine is then bottled and sealed with a crown cap.
3. Second Fermentation
This fermentation happens inside the bottle and means that the carbon dioxide that usually escapes is now trapped and dissolved into the wine, creating the future bubbles. This makes somewhere between 4-6 atmospheres of pressure, in the final product, which for reference, is about double the pressure of your car tyres. This is why a sparkling bottle needs to be much heavier than your usual bottle. The alcohol has also increased slightly at this point. Once the fermentation is complete, the dead yeast cells, called the lees, settle and remain in the bottle.
And now, we wait. Well, a bit more is going on here than meets the eye. This is where the wine develops some of those toasty, brioche characters. In winemaking we call it autolysis and it’s where the dead yeast cells are broken down further as the wine ages. This adds to the rich bready aromas and gives the final wine a creamy texture. Certain sparkling wines, like champagne, must be aged for at least 15 months or in the case of vintage champagnes, for 30 months. This contributes to the layers of flavour and structural complexity that traditional method wines are prized for. As a general rule of thumb, the longer such wines are aged, the more autolytic characters you get.
The aim of this step is to get the lees down to the neck of the bottle so that you’re left with a nice clear wine. This can be done in a couple of ways: by hand or by machine. By hand, the bottles are kept in a riddling rack and quarter turned at regular intervals and gradually angled downwards to encourage the yeast downwards. This is incredibly time consuming and labour intensive, so most producers use a gyropalette, which simulates the riddling process, but it can do a whole crate’s worth of wine without lifting a finger in a shorter space of time.
Now we come to the most dangerous step in the process. We need to expel the lees that have now moved into the bottle neck. To do this, the bottle’s neck is placed in a sub zero solution that freezes the lees as a solid plug. When the crown cap is removed, the pressure in the bottle shoots the plug out with a pop!
The final step is to replace any of the wine that may have come out during the disgorging process and make any adjustments to the final wine. This addition is called the liqueur d'expedition or dosage. The bottle is then sealed with a cork and wire cage, called the muselet, and labelled ready for distribution.
So the next time you open a bottle of Champagne or traditional sparkling wine, take a moment to note fine delicate bubbles and the complexity of the flavour profile, and consider the long road it’s taken to be in your glass. There’s a reason why sparkling wines are such a joy to drink and even open. If you’re looking for something to charge your glass, explore our extensive range of sparkling wines here.