The undeniable diffusion of Prosecco on a global level in recent years has led to the term itself becoming the identifier of the entire category of sparkling wines. A bit like when we say scotch to indicate adhesive tape, or scottex for a paper towel. So let's do a bit of order in this sea of bubbles starting from the textbook definition of sparkling wine, that is, that wine in which dissolved carbon dioxide is present which generates an overpressure of at least 3,5 absolute atmospheres inside the bottle. Carbon dioxide that is formed either as a result of a natural refermentation of the wine, or by artificial addition of it. When we finally uncork our sparkling wine bottle, the pressure drop creates the effect of effervescence, that is, bubbles and a more or less persistent froth are formed on the surface of the wine. But at this point how is a sparkling wine made? The most important and most used methods are two: the Classic Method and Charmat method (or Martinotti). For both we start from a base wine to which a mixture of sugars and yeasts is added in such a way as to have a refermentation that will produce the effervescence of the wine itself. And now let's see the differences between the two methods!
In Classic Method, as mentioned above, we start with the identification of a base wine or an assembly (vintage) of base wines different from each other for grape varieties used, different vintages or for origin from different vineyards. This operation is of particular importance because it will directly affect the quality of the final product. If the cuvée is composed of grapes for at least 85% of the same vintage, then the sparkling wine can be defined as "vintage”And the vintage can be reported on the label; otherwise, you have a sparkling wine sans année. At this point the wine is prepared for the second fermentation, adding a mixture made up of sugar, yeasts and nitrogenous foods (liqueur de tirage) and it is bottled by closing with a temporary crown cap.The new fermentation continues in rooms at a controlled temperature between 10 ° and 12 ° for several months, during which the second fermentation takes place, i.e. the formation of carbon dioxide in the bottle . Then follows a phase of maturation, during which the sparkling wine rests on its lees, while the yeasts release some substances that make the scent and taste of the sparkling wine in question typical. After several months, when the sparkling wine has reached the desired level of maturation, the lees deposit is eliminated through the practice of remuage. The bottles are arranged on so-called perforated shelves desks in an almost horizontal position. Little by little, on a daily basis, the bottles are tilted, shaken and rotated by 1/8 of a turn in order to reach an almost vertical position with the cap facing down. In this way the lees deposit ends up in a small cylinder (bidule) placed in the crown cap.
Nowadays this operation can be automated and is carried out by the giropalette, large rotating baskets, containing the bottles. Finally, the yeast deposit is eliminated from the bottle with disgorgement (dégorgement). Disgorgement can be done in two ways: à la volée, that is, uncorking the bottle quickly so that the internal pressure of the gas pushes out the deposit, and then quickly recaps it; or à la glace, procedure that consists in arranging the necks of the bottles in a solution of water and propylene glycol (non-toxic) at a temperature of -25 / -30 ° C for 12-15 minutes, so that the deposit freezes and then uncorks and lets it come out .
The wine that is lost with the disgorging operation is replaced with similar wines or wines from previous vintages. Sometimes, some liqueur d'expedition, or dosage syrup, containing sugar and wine distillate. The recipe of this liquid varies from producer to producer and is the way in which the producing company tries to give a personal imprint to its sparkling wine, which will have a taste and a bouquet of aromas different from all the others. In the event that the topping up takes place with a liqueur d'expédition to which no sugar has been added, we will have a sparkling wine called pas dose (o zero dosage). The last step of this method, with which the famous Champagne or sparkling wines of Franciacorta, Oltrepò Pavese or Trento DOC are made, for example, is to close the bottle with the cork and the characteristic metal cage.
The other method of sparkling wine production, with which the famous Prosecco is produced, is the Charmat method (o Martinotti), which differs from the Classic one because the second fermentation takes place in large autoclaves, rather than in the bottle. This process can last only 2-3 months and in this case we speak of Short Charmat, or about 6 months and in this case we can speak of Long Charmat. This means that, unlike what happens with the Classic Method, the wine remains in contact with the yeasts for shorter periods. At this point we just have to uncork a nice bubble remembering that the bang, according to the rules of the sommellerie, is only allowed on New Year's Eve.
Which bottle to uncork? There is definitely plenty of choice! But maybe we'll talk about this later!
