As harvest draws to a close, the selected grapes arrive at the winery to begin one of the key stages in winemaking, when the grapes become must and the sugar that the fruit contains is converted into alcohol. It is known as alcoholic fermentation and it is when we can start to talk about the grapes’ transformation into wine.
The first musts
When the grapes arrive at the winery, they are de-stemmed. We remove the stalk or the green parts of the bunches and separate the grape berries. We fill our tanks so that the skins of the grapes – known as pellejos or hollejos in Spanish – split open under pressure without crushing the pips. When the must starts to ferment, it generates carbon dioxide, which pushes the skins to the top of the tank, while the liquid remains at the bottom. The skins form what is known as the cap.
While the alcoholic fermentation is taking place, the must is pumped back over to wet or break up the cap. At LAN, we try to ensure that the cap remains submerged in the must. This way, the coloured compounds and the aromatic precursors that are found in the skins remain in contact with the must. With the pumping-over, this movement of the must from the bottom to the top activates the yeasts as they come into contact with the oxygen, extracting all the colour, balancing the alcohol and regulating the temperature of the must…
As the days pass, the must is transformed into wine. The amount of sugar decreases, and the alcohol increases. When it is complete, it is followed by malolactic fermentation, when the malic acid is converted into lactic acid, being a softer acid that gives the wine a more creamy texture on the palate.
LAN’s team of winemakers follows each one of the stages very carefully to try to “respect the raw material” as best they can, always preserving the characteristics of the vineyard in each of the phases of fermentation and ageing.