Santa Margherita

As soon as the grapes have been picked they are taken to the cellar. Those destined for use in red wine are crushed and de-stemmed, using special equipment that does not damage the skins and pips of the grapes. It is in the skins, in fact, that we find the noble polyphenols that are responsible for the wine’s color and also –in part – for its structure. The stems and pips, on the other hand, are normally discarded, because they give rise to aggressive and unpleasant taste sensations.
The must or juice is then transferred to the tank where the alcoholic fermentation will take place: this is filled to four-fifths of its capacity. An appropriate dose of sulphur dioxide is then added which, besides having an anti-oxidant and disinfectant role, also helps to loosen the coloring matter contained in the skins as well as to determine the selection of the yeasts.
The activity of the yeasts (Saccaromices Cerevisiae), which are responsible principally for the transformation of the sugars into alcohol, also leads – during the fermentation – to an increase in temperature. Modern technology allows for this to be controlled (at 24°–28° C), in order to favor the vitality of the yeasts and encourage the preservation/formation of fragrant aromas. Another product of the transformation is carbon dioxide, which is clearly perceptible because of the gurgling of the must. This is the “tumultuous” stage of the fermentation: the solids, pushed upwards by the gas, start to rise to the surface, forming a layer – referred to as the “cap” - on top of the wine. This cap has to be continually broken up and re-immersed in the must so as to encourage the extraction of the coloring matter.

This may be done using the following methods:
•    pumping-over, carried out by taking the must from the bottom of the tank and pumping it to the top, where it is sprayed onto the cap so as to break it up;
•    punching down the cap, in which one uses special types of equipment (such as pistons, screws or blades) in order to exert mechanical pressure on the cap and so break it up into various parts;
•    délestage, which consists in transferring the fermenting must into a separate container and then reintroducing it into the original tank once the cap has sunk to the bottom.

When the daily measurements (which are usually carried out in the morning and the evening) show that the percentage of alcohol in the wine has stabilised, it is more than likely that the fermentation is over. This usually occurs when all the fermentable sugars have been transformed into alcohol, but it is possible (in the case of musts that are very rich in sugars, such as those from partially-dried grapes) that a certain quantity of sugars is still present and that the yeasts – partly because of the antagonistic activity of the alcohol that they have produced – will become less efficient and eventually be unable to continue doing their job.

The wine that has been obtained is cloudy and is full of gas and solid matter. The liquid must therefore be separated from the solids. This stage is referred to as draining, or drawing, off.
After this operation is concluded, the wine is clear and clean and may be transferred into stainless steel tanks (if the wine is to be drunk young) or into wooden barrels if it is to be aged.

Nearly always, especially for wines which are to be aged, the alcoholic fermentation is followed by malolactic fermentation, a process which transforms malic acid into (the gentler) lactic acid, thereby softening the wine and giving it a more mature, complex bouquet.