BOTTLING: the basic wine, traditionally defined as cuvée, is bottled with the addition of selected yeasts, sugar and nutritional nitrogenous substances. It is then capped with a metal crown cap.
CAPTURING THE SPARKLE (OR REFERMENTATION): The bottles are now put away in a horizontal position during which a second fermentation takes place lasting around 40 days. During this period, the yeasts transform the sugars into alcohol (increasing the alcoholic degree) and carbon dioxide (creating pressure within the glass bottle). These yeasts must have special characteristics in order to react inside a liquid which is already rich in alcohol, at low temperatures and under increasing pressure.
AGING: Once fermentation has concluded, the lifeless yeasts deposit within the bottle and rest on each other for a long time thereby giving the sparkling wine the fragrance and flavour which are typical of the Classical method. This process lasts anywhere from fifteen months up to ten or more years, under a constant and low temperature.
UNLOADING: While the wine is aging, some winemakers unload the bottles, in other words they are taken down from where they are resting (pallets or shelves) and the bottle shaken in order to create further contact between the wine and the yeasts.
REMOIGE: Once aging has concluded, the bottles are placed on special stands called pupitre, in a position which is almost vertical. This favours the yeast sediments to collect in the neck of the bottle. This can happen only if the cellarman carries out remoige repeatedly (rotations of the bottle on itself). Remoige can also be done by using special machinery.
DISGORGEMENT: The sediments that are now in the neck of the bottle must be removed. To do so, the neck must be frozen and the deposits of yeast are removed by taking of the cap and allowing the pressure inside the bottle to push the block of ice from within.
DOSING: When disgorgement is carried out, not only do the frozen yeast sediments come out but so does some of the wine. The bottles are immediately topped off with “liqueur d’expédition”, a mix which each winemaker has his own recipe for, composed mainly of older sparkling wine, brandy and/or brown sugar in order to soften the flavour of the wine.
CAPPING: The bottle is sealed with a classical cork stopper covered by a metal wine cage or muselete and left to rest a few more months before being placed on the market.
The Martinotti Method - prosecco is made with the Martinotti Method
PREPARING THE BASIC WINE: It is very important that the basic wine undergoes specific filtration measures in order to make its proteins and polyphenols as stable as possible.
REFERMENTATION IN VATS/AUTOCLAVES: the basic wine is placed inside a very large stainless steel container called an autoclave. Sugar and yeasts are added and these start a second fermentation.
Even during the second fermentation, which takes place at around 15°C and lasts around 10-15 days, the yeast transforms the sugar into alcohol and carbon dioxide. Since the autoclave is completely sealed, the carbon dioxide remains dissolved in the liquid and on average reaches 5 atmospheres. At this point, the wine is brought to about 0°C and left to rest on the yeast sediments for 1 to 12 months (if it’s 12 months, then the method takes on the name of LONG MARTINOTTI).
REFRIGERATION AND FILTRATION: Once the right pressure has been reached, the sparkling wine is ready for the final cleaning, the deposits of yeast must be removed. In order to remove them, there are mainly two ways. The first is to filter the sparkling wine and separate the yeasts. This always happens at the same level of pressure (isobarically), moving the wine to another autoclave where the temperature is lowered below zero thereby refrigerating it and reaching tartaric stability.
The second way on the other hand refrigerates the wine in the same fermenting autoclave and once tartaric stability is reached, the wine is filtered so as to eliminate the yeasts and leave the product clear.
ISOBARIC BOTTLING: This is carried out simultaneously with a sterilizing filtration or microfiltration always under pressure. Biological stabilization and attention to oxydating phenomena are the main problems which the winemaker must worry about during this phase.
CAPPING: Generally speaking, this is done with corks and a metal wine cage. The bottles are kept in the cellar for a few months before being packaged and placed on the market.
Sur Lie Method
“SUR LIE” in French (or “COL FONDO” in Italian), literally means “on dirt” (yeast). It is the oldest way to produce Prosecco sparkling wine. Before the arrival of autoclaves, or vats that are under pressure and used for the Charmat-Martinotti method, the SUR LIE method re-fermented the wine inside the bottle without however carrying out dégorgement, or in other word the technique used in the classical method to remove the yeast deposits and thereby obtain a clear wine. With the SUR LIE method, you have a wine which still contains yeast. There are two ways to drink it: remove the sediments by letting the wine slowly decant in a decanter as if it were an aged red win, or by simply shaking the bottle so that the sediments all mix.
The Ancestral Method is an antique technique of wine-making which still today would position itself between the Martinotti-Charmat Method and the Classical Method. It consists in lightly pressing the grapes in order to extract the autochthonous yeasts from within, followed by fermentation in temperature-controlled stainless steel. By acting on the lower temperatures, fermentation is initially slowed down and then blocked maintaining just enough sugar so that it can start again after bottling without having to add more sugars or yeast. The yeasts inside the bottle favour, as the French say, the formation of a slightly sparkling “petillant”. This is the method which was historically used in Champagne before the Classical method was introduced and which would bring to the wine a more complex organoleptic structure. Indeed, the recipe did not foresee the disgorgement of the yeast sediments, which were left inside the bottle which was capped with a crown cap, thus favouring “sur-lie” aging or, other words, aging on its own yeasts, but also a slightly cloudy and hazy appearance in contrast with the clarity and intense brightness of the bubbles we are used to seeing.