Sparkling Wine Production Explained
Prosecco, Lambrusco, Cava, Champagne. There are many sparkling wines but how do those beautiful, effervescent bubbles get there? There are a number of options with each one leading to a unique style of sparkling wine. Here are the six main methods.
CHAMPAGNE METHOD or TRADITIONAL METHOD
The champagne method is the process used in the Champagne region of France to produce the sparkling wine of the same name. This method is also popular in other parts of the world such as Italy, Spain, and Portugal however EU labelling laws prevent the method being referred to as the champagne method, which is reserved for sparkling wines from the Champagne region and instead insists the method is referred to as the traditional method.
The production process
Fermentation: The first fermentation occurs like any other wine in barrels to produce the base wine.
Second fermentation: Once the first fermentation process is complete the wine is bottled with an amount of sugar and yeast added. The bottle is closed with a temporary cap before being laid horizontally in a cellar for the yeast and sugar to ferment. As the yeasts feed on the sugar they give off carbon dioxide, which is trapped in the bottle - the source of the fizz! Eventually, the yeats die and become lees. The lees create texture and complexity in the wine and will be left in the bottle for varying lengths depending on what the winemaker is trying to achieve in terms of taste.
Riddling: Having completed the second fermentation the lees need to be removed from the bottle. To do this the bottles are stored at an angle of 45 degrees and shaken and turned on a daily basis with the angle of the bottle being gradually increased. Eventually, the lees make their way to the neck of the bottle.
Disgorging: To remove the lees a small amount of liquid in the neck of the bottle is frozen. The temporary cap is then removed and the pressure in the bottle pushes out the frozen liquid, expelling the lees.
Dosage: Before final corking, the winemaker tops up the bottle with a mixture of the base wine, sugar, and sulfur dioxide. This process is known as dosage. The amount of sugar used will determine the sweetness of the wine.
Next time you're picking up a bottle of sparkling wine made in the traditional method have a look at the label for these words denoting the sweetness (listed here from sweetest to driest)
- ‘doux’ (sweet)
- ‘demi-sec’ (half dry)
- ‘sec’ (dry)
- ‘extra-sec’ (extra dry)
- ‘brut’ (very dry-dry)
- ‘extra brut’ (very dry)
- ‘brut nature/brut zero/ultra brut’ (no additional sugar added)
Wines made using this method: Champagne, Cava, Espumante, Franciacorta.
CHARMAT METHOD or TANK METHOD
This method was originally developed by Federico Martinotti in 1895 and later refined by Eugene Charmat in 1907. Using this method wines can be produced at a considerably lower cost than traditional method wines but that doesn’t necessarily mean lesser quality. Instead, this method produces fresher, crisper sparkling wines that are youthful and easy drinking.
The production process
Fermentation: As with the traditional method the first fermentation occurs in barrels to produce the base wine.
Second fermentation: Rather than being undertaken in the bottle the second fermentation instead takes place in a pressurised stainless steel tank. The base wine is added to the tank along with sugar and yeast and so begins the process of the second fermentation with the yeast giving off carbon dioxide, which is trapped in the tank.
Filtration: Once the yeast dies or the winemaker stops fermentation by cooling the tank the wine is filtered to remove the lees.
Dosage: This happens directly in the tank with the winemaker adding a mixture of the base wine, sugar, and sulfur dioxide.
Bottling: To avoid the carbon dioxide escaping the wine is transferred under pressure from the tank to bottles, which are immediately corked.
This method is a mixture of the traditional and tank method. Secondary fermentation takes place in bottles but once this process is finished the bottles are emptied into pressurised stainless steel tanks so the lees can be filtered off before the wine is dosed and transferred to new bottles.
Using this method allows the sparkling wine to take on the characteristics associated with the traditional method without the expense and is commonly used for champagne in bottles larger or smaller than the standard 375ml, 750ml and 1.5l formats.
Wines made using this method: Champagne in outsized bottles, sparkling wines from New Zealand and Australia.
This method is also known as the Russian method, which is where it was created and is similar to the tank method. The second fermentation takes place in multiple pressurised stainless steel tanks where the base wine, sugar and yeast are continuously circulated. Some of the tanks contain oak shavings where the lees accumulate to provide toasty, yeasty flavours as well as help to clarify the sparkling wine.
Wines made using this method: Soviet Champagne, Sket.
The oldest method of producing sparkling wine predating the traditional method by at least 200 years. This method is used to produce petillant-naturel or pet-nat wines and the result is a sparkling wine that is cloudy, highly aromatic and typically low in alcohol content.
There’s no secondary fermentation with this process. Instead, the fermenting wine is transferred from barrel to bottle before the first fermentation is complete. The wine continues its fermentation process in the bottle and once complete the wine can be filtered and replaced into the bottle without additional sugar however many winemakers are now choosing not to filter.
Ancestral method sparkling wines are often seen as high-quality and are typically produced by small, organic growers.
Wines made using this method: Gaillac, Bugey Cerdon, Blanquette de Limoux, various German and North American sparkling wines labelled as such.
The least said about this method the better! Think SodaStream. This method involves adding carbon dioxide into a still wine from a carbonator and to no surprise is associated with very low-quality sparkling wine. If you’re buying a sparkling wine in the EU look out for and avoid wines where the label says 'aerated sparkling wine' and 'aerated semi-sparkling wine' along with 'obtained by adding carbon dioxide' or 'obtained by adding carbon anhydride'.