Have you ever wondered how sparkling wine is made? Keep reading and you’ll find the answer and much more!
The wine-making process is where all the magic happens and that’s where a lot of “ah-ha” moments happened for me. As we’ve seen in the winemaking guide, from grape juice, alcohol is produced for example. That was already a nice trick and here new magic happens, bubbles are formed but combining yeast and sugar to the base wine. How is that possible? Keep reading and you’ll find out!
I’ve organized the content below in small sections to make it easy to read. I must confess I’m quite happy with the research and work done. I hope you’ll find it useful too.
Use the table of content below to jump straight to the section. In this article you’ll learn more about:
Are you ready? Let’s begin!
The Traditional Method
In the traditional method or méthode traditionnelle in French, the fermentation happens in the bottle. This method produces the highest sparkling wine quality albeit at the highest costs. and it’s considered the classic way of producing sparkling wines. Some of the most famous examples are Champagne, Cremant (France), Cava (Spain), and Franciacorta (Italy).
The traditional method follows the following steps:
- The Base Wine
- 2nd Fermentation
- Yeast Autolysis & Aging
The Base Wine
It is usually a blend of dry white wines, high in acidity and low in alcohol. Check out our winemaking guide to learn more about it. The blend is key to determine the house style of the wine, to improve its balance and complexity. Of course, the blend formula is secret. It’s like the Italian grandma secret sauce recipe in a way ☺.
Yeast and sugar, aka liqueur de triage, are added to the base wine. The bottle is sealed with a crown cap, placed horizontally and the second fermentation starts. As seen in the winemaking process article the yeast transformed the sugar into alcohol and CO2 which forms the sparkle. The pressure within each bottle is between 5-6 atmospheres. That’s nearly 3 times the pressure you have in a motor-car tire! Once all the sugar has been transformed the abv has increased by roughly 1.2%-1.3% and the yeast forms the ‘lees’ which sediment in the bottle.
Yeast Autolysis & Ageing
The wine will now age in the bottle for at least 15 months, 12 of which in contact with the ‘lees’. This is where the typical bread and biscuit flavors come from, aka autolytic flavors. The length of the contact directly impacts the flavors’ intensity, complexity, and the wine’s price.
It’s now time to remove the lees to avoid haziness in the wine. The bottles are very slowly moved from a horizontal to a vertical upside-down position. This allows the lees to deposit on the neck of the bottle.
The neck of the bottle is now frozen so that once the cap is removed, the frozen lees are ejected from the bottle.
It’s now time to top up the wine of the liquid that has exited from the disgorgement. Wine and sugar, aka liqueur d’expédition, are added to the wine. The amount of sugar will determine the sweetness of the wine. The majority will be Brut, i.e. with a minimal amount of added sugar up to 12 g/l. As the wine amount increases the wine will progressively be sweeter. Demi-Sec for example is a medium sweet wine with 32-50 g/l.
The bottle is now resealed with a thick cork and a wire cage and ready to be sold and consumed.
The Charmat Method (aka Tank or Martinotti Method)
In the Charmat Method, fermentation happens in a tank. The Charmat method has various names: Metodo Martinotti in Italian or Tank Method in English. This method is simpler, faster, and cheaper compared to the traditional method. The most famous example is Prosecco DOC (Italy).
The Charmat method follows the following steps:
- The Base Wine (see above)
- 2nd Fermentation
The key differences with the Traditional Method are that:
- The 2nd Fermentation happens in a pressure-resistant tank for about 10 days.
- The ‘lees’ are removed by Filtration.
- The dosage is generally Brut or Extra Brut from Prosecco.
The end result is a wine that has maintained the taste of the base wine since it has not undergone the autolytic process, i.e. it has not rested on the ‘lees’ for a long period of time. It’s for this reason that generally this method is used for aromatic or semi-aromatic grapes.
The Ancestral Method
The Ancestral Method or Méthode Ancestrale in French is the oldest way to produce sparkling wine by almost 200 years and counting. This method is used to produce sparkling wine in a “natural way” as additions from Dosage don’t take place here.
The most famous examples are: Blanquette de Limoux and Pétillant-naturel or pét-nat (France).
The Ancestral method follows the following steps:
- The Base Wine (see above)
- Alcoholic Fermentation
The key differences with the Traditional method are that:
- The wine it’s bottled whilst the Alcoholic Fermentation hasn’t finished yet.
- There’s no Disgorgement and Dosage, although the wine is usually Filtered.
The end result is a sparkling wine with low alcohol and usually with some lees residual.
The Asti Method
The Asti Method wine is used to produce primarily sweet sparkling low alcohol wine. Asti DOCG or Asti Spumante DOCG (Italy) are the most famous examples. This method is used to preserve as much as possible the original wine flavors by limiting the alcoholic fermentation.
The key differences with the other methods are that:
- There is only one Fermentation as the process doesn’t start with a Base Wine. Instead, yeast and sugar are added to the juice and fermented in a tank where the bubbles will form.
- The Fermentation is stopped before the yeast consumes all the sugar and increases the wine’s abv.
The end result is a sweet sparkling wine low in alcohol. For the dry version, the fermentation will last a bit longer so that the residual sugar is reduced.