According to EU regulations, sparkling wine may be called only when carbon dioxide (CO2) comes from first or second fermentation, but is not injected. Two main methods are being used to produce EU sparkling wine – Charmat and Traditional.
Traditional Method (Methode Traditionelle)
This is a classical way to make a sparkling wine. Main wines produced today using traditional method are Champagne, Cava, Franciacorta and Cap Classique. On the other hand this method can be used for any quality EU wine. It is used mainly for premium wines because it is expensive in terms on labour, space and time.
TRADITIONAL METHOD contains of next stages: first fermentation, assemblage/blending, liquer de tirage, secondary fermentation, aging, remuage/riddling, disgorgement and dosage.
First fermentation of wine is a basic step to produce a base wine for further sparkling wine production (first fermentation of wine discussed in “Wine making in Vineyard and Winery” section of our website). During this stage wine has a lot of acidity and relatively low alcohol level. Base wine is more acidic than regular still wine. Usually winemakers use big stainless steel tanks for the first fermentation.
Assemblage or blending
Second step is assemblage or blending – during this process winemaker is trying to reach a perfect style and quality for its desired final product. It is possible to use a single variety of wine (from a single grape) or to mix several different grape varieties, different vineyards or even different harvests. Especially for this stage winemaker creates a reserve of wines of a particular harvest for aging. This reserve wine might be used to blend a sparkling wine.
Liquer de tirage
After the blending wine is bottled into a dark, strong bottles and little amount of so called “wine cocktail” (Liquer de tirage) is added. Liquer de tirage is simply yeasts and sugar, which will allow secondary fermentation to happen, rewarding wine with an all-important fizz as well as additional aromas and taste complexity. Carbon dioxide can not leave the bottle, so it dissolves into the wine. Pressure up to 6ATM is created inside the bottle. Bottles lays horizontally during the secondary fermentation (sur latte). Longer the wine rests on the lees of the second fermentation, more it is aging, more chance it has to pick up flavor from the dead yeast cells – this process is known as yeast autolysis.
Most regulations for traditional method sparkling wines specify ageing on lees time. Minimum time is 9 months while for non-vintage champagne it is 15 months. Vintage champagnes are aged for several years. Most obvious changes in wine flavours and complexity occurs after 5-10 years on lees.
After aging riddling or remuage starts – it is the remove of the deposit that would make wine cloudy. Traditionally bottles were moved from horizontal to an inverted vertical position by hands, by people, called remueurs, who would shake them and the deposit every time they move them towards the invert vertical position in special pupiters or riddling racks. Today due to expensive labour, more for industrial wine, mechanical machines called gyropalette are used for this process.
Disgorgement and dosage
Final steps of sparkling wine production by traditional method are disgorgement and dosage. Collected deposit, which is frozen using nitrogen in the bottle neck, is removed during disgorgement. During this stage small amount of wine might be lost, so final bottle of sparkling wine is filled with dosage - little amount of wine and sugar cane mix (liqueur d’expedition) or even reserve wine. After that bottles are closed with cork, wire muzzle and are prepared for labeling.
This method was first developed and patented in 1895 by the Italian Federico Martinotti. It was later further developed by the inventor Eugène Charmat in 1907, after whom this method is named today. Its advantages are that it is much cheaper, faster and less labour intensive than the traditional method.
During CHARMAT method, the base wine is placed in a stainless steel pressure tank, together with sugar and yeast.
Rapid fermentation starts (the fermentation is typically arrested by cooling the wine to -5 C0) )that converts sugar into alcohol and carbon dioxide.
Later yeast are filtered and removed, wine is bottled.
This style of sparkling wine production is most likely to taste like a still wine with bubbles, representing wine grape features. It does not have the additional attributes that arrive from the bottle fermentation (yeast or baked bread flavors and aromas).
CHARMAT production method is widely used in the USA, Italy (mainly Asti province, and in Prosecco wines), also in Germany to produce Sekt wines.