Sparkling wines, for most of consumers, are uncorked in particular occasions, to celebrate a particular event and they are bought soon before their consumption. Witness of this behavior are the sales that mainly concentrates in certain periods of the year, when in shops shelves are filled with this style of wine. Nevertheless, sparkling wines are very versatile, and they can certainly have a special place in the table to be paired to a whole meal: from appetizer to dessert, sparkling wines always suggest a good chance to be uncorked. There are few consumers who think about letting them to rest in the cellar, or however to give them some time in order to develop complex qualities, therefore giving them a new sensorial and organoleptic dimension. It should be said mature sparkling wines are not always appreciated: their sensorial profile frequently changes in a radical way, frequently becoming a distant memory of what people mainly expect from a wine of this type.

 It should be said not all the sparkling wines can be aged for a long time in bottle, a quality which is mainly determined by the technique used for production. As it is commonly known by most of wine lovers, most of sparkling wines are produced with two techniques very different one from each other - classic method and Charmat method - and both are based on the same principle, that is the refermentation of a wine. This process is started by using the same principle in both method, however the way with which the methods are completed is radically different. The refermentation is started by simply adding to a wine a mixture of yeast, sugar and substances capable of activating the yeast. Sugar is essential to give yeast indispensable substances for its activity, as in a dry wine the presence of sugar is virtually absent.

 The way with which the refermentation and aging is continued is however different in both cases. In the Charmat method - also known as Martinotti method - the refermentation is done in a closed tank, whereas in the classic method the refermentation is done in a bottle. The final result is however different: each method has specific characteristics as to give the wine specific organoleptic quality and personality, although, in both cases, producing effervescence in wine. The choice of a production method is fundamental for the type of sparkling wine to make, and it should be noticed not all the grapes give their best with one method or the other one. There are grapes, for example, giving pleasing aromatic qualities to the sparkling wine provided it is produced with the Charmat method, whereas the same grapes could give insignificant results in case they are being used with the classic method.

 The wine destined to the production of a sparkling wine must be specifically produced for this purpose. Wines suited for the production of sparkling wine must have - in general terms - two fundamental characteristics: an evident acidity and a modest quantity of alcohol. These two characteristics, which would make any table wine unpleasing, are in fact fundamental in order to make a sparkling wine with balanced gustatory qualities. Acidity will be fundamental for the balance of the liqueur d'expédition, in which can also be found sugar, an element always found in classic method sparkling wines with the exception of the so called “pas dosé” wines, that is the ones in which the mixture of sugar is not added at the end of the refermentation. The low quantity of alcohol in a base wine is essential in order to avoid a final product with an excessive quantity of alcohol - therefore causing a significant sensorial unbalance - as during refermentation the yeast, besides enriching wine's organoleptic qualities, will also produce alcohol.

With a long aging in bottle, the color of sparkling wines gets a golden yellow hue

 The two production methods, despite their final goal is to give effervescence to a wine because of the solubilization of carbon dioxide, are made of procedures and method very different one from each other. Let's try to understand them, although in a quite short way, however enough to understand their differences. Of the two methods, the most simple and immediate one is the so called Charmat method. This method was invented in 1895 by Federico Martinotti, at the time he was the headmaster of the Royal School of Enology of Asti. It will be in 1907 this method will become very famous, when the French engineer Eugène Charmat studied and improved Federico Martinotti's method. This method of production is today known as “Charmat method” or “Martinotti method”, and it is based on the use of a closed tank, that is a hermetically sealed container and in which will develop a certain pressure during the refermentation of the wine which will then become a sparkling wine.

 This method provides for three different methods - however all based on the same technology - each destined to the production of a sparkling wine with specific characteristics. The three methods are respectively called Short Charmat - or simply Charmat - Long Charmat and Charmat for sweet and aromatic wines, the latter used for the production of the famous Asti and Brachetto d'Acqui. The two latter methods derive - as a matter of fact - from Short Charmat, properly adapted in order to give the wine specific organoleptic qualities. Before understanding these two “adapted” methods, let's see, in short, the phases characterizing the short Charmat method or simply “Charmat”. The process starts with the production of a base wine - which can also be made of more wines - then transferred to the container of the closed tank.

 The wine is added with a mixture of yeast, sugar and substances which will favor the activation of yeast. The tank is then hermetically sealed and yeast, thanks to the presence of sugar, will start the second fermentation in the wine. Fermentation, as it is commonly known, produces alcohol and, as a byproduct, carbon dioxide that, as it cannot get out of the closed tank, it will saturate the container and it will be subsequently solubilized to the wine, producing the characteristic effervescence. The refermentation inside the tank has a variable duration from few weeks to some months, generally 3 and not more than 6 months. At the end of the fermentation, the wine - which at this point is a sparkling wine - is separated from the sediments and filtered, it is then added, if needed, a liqueur d'expédition, therefore bottled in isobaric conditions, that is at the same pressure inside the tank in order not to lose the precious carbon dioxide. This rapid method of production however gives a wine with bubbles of a pretty big size, when compared to those produced by the classic method.

 The “long” Charmat method differs from the short method for the duration of the process. This variation was invented by wine maker Nereo Cavazzani at the end of the 1970s. Long Charmat method - also called Cavazzani method - provides for a refermentation and a subsequent aging in a closed tank for a period from 6 to 12 month. The duration is not the only difference with the “short” method. The closed tank used for the Cavazzani method is equipped with screw agitators which will bring the sediments of fermentation in suspension. This favors the enrichment of wine's body and gives it a more complex sensorial profile, a quality generally common in sparkling wines produced with the classic method. The Charmat method for sweet wines is based on the fermentation of the must produced from aromatic grapes - such as Muscat Blanc and Brachetto - while avoiding the completion of fermentation therefore obtaining a naturally sweet wine and with a low alcohol by volume. It should be noted in this method it is being used the must instead of a wine.

 The classic method is more complex and, in particular, takes very long times, even years, in order to obtain sparkling wines of high quality and with complex organoleptic characteristics. The method provides for the refermentation of the base wine in a bottle, the very same bottle which will be used for its commercialization. The bottle is sealed with a crown cap, in order to ensure a perfect seal even with the high pressure developing inside the bottle during fermentation. The base wine is added with a mixture of yeast and sugar, then bottled and allowed to rest for a long period in order to have time doing its precious job. Carbon dioxide produced during fermentation rapidly saturates the bottle therefore causing the subsequent solubilization in the wine and making it effervescent. Sediments of fermentation - the precious secret of classic method - enrich the wine by giving it body and, in particular, complex and remarkable organoleptic qualities.

 The chances for a good aging of a sparkling wines depend on many factors, first of all, the method used for the production. Grape varieties play and important role, as well as acidity and the quantity of alcohol - just like in white wines - and contribute to the keeping of a sparkling wine. The aging of a sparkling wine on its fermentation sediments - before dégorgement - represents another element which favors a better keeping, a factor which is also determined by the duration of time. This condition is typical in classic method sparkling wines, which can be aged in the bottle for many years before dégorgement, whereas for those produced with the Charmat method, sediments - besides being filtered - stay in contact with the wine for few months. Among the most important factors for the keeping of a sparkling wine, we have oxygen, or, better to say, the absence of oxygen.

 In the bottle of a classic method sparkling wine, oxygen is virtually absent, as the “empty” space is completely occupied by carbon dioxide. This condition avoids the oxidation of wine and - in theory - ensures the sparkling wine a virtually endless keeping. Oxygen gets in contact with the classic method sparkling wine at the moment of dégorgement, the indispensable operation with which the sediment is expelled in order to get a limpid wine. From this moment on, the small quantity of oxygen inside the bottle will start a slow but however unavoidable oxidation, a condition that - as a matter of fact - allows the aging and the organoleptic development of the wine. It should be said a mature sparkling wine does not always meet the appreciation of consumers. The qualities developing with time, give these wines a dimension of remarkable sensorial interest, most of the times far away from what one would expect from a wine of this type.

 In mature sparkling wines, in fact, it will be perceived a more pronounced roundness, although keeping an evident acidity, and aromas will develop tertiary qualities recalling smells of jams, honey and dried flowers, as well as strong aromas of bread crust and dried fruits. To the taste, the typical acidity is added to a pretty evident roundness, a characteristic not always appreciated in this style of wine. The keeping of effervescence - and therefore of the pressure inside the bottle - depends of the sealing capacity of the cork and its permeability. Sometime happens that a mature sparkling wine loses most of its effervescence, greatly influencing taste and balance. Also the color, because of the effect of oxidation, gets deeper hues of intense and brilliant golden yellow, a color which can also be observed in nuances. Finally, it should be noticed sparkling wines most suited to the keeping in bottle are the ones produced with the classic method, capable of aging for some years. Among Charmat sparkling wines, the most longeval ones are those produced with the “long” method, the least longeval ones are those produced with the “aromatic sweet wines” method.