Washing

General principle

In the development of the white wines and rosy, the must obtained by bleeding or direct pressing must be clarified before fermentation: it is the Débourbage. This stage is essential if one wants to obtain a fruity wine and Net from an aromatic point of view, without odors vegetable or coarse or sulfur (odor/taste of bourbes, H2S, " rubber brulé" , " cabbage bouilli" …).

The level of required washing ranges between 50 and 200 NTU: in lower part the risks of difficult alcoholic fermentation increase, above the clarification is insufficient to achieve the goals of aromatic smoothness of the wine. A too clear must, too " débourbé" do not comprise enough nutrients and support for a good viability of yeasts.

The simplest technique of the washing consists of a static decantation of the juices, generally after a enzymage to hydrolize the pectic compounds which maintain a too great viscosity of the juices and prevent the spontaneous clarification. The enzymes are on the other hand ineffective at too low temperature (lower than 5 °C).

The temperature of the juices at the time of washing is also determining. A fresh temperature (10 to 14 °C) facilitates the sedimentation of the bourbes and reduces the risks of development of contaminants which can spontaneously engage a still undesirable alcoholic fermentation at this stage. In the same way, the sulphiting (SO2) and hygiene take part in the control of the possible contaminants.

Techniques used

Several techniques of washing are usually used. One generally differentiates the techniques from washing " statiques" such as the decantation (explained above) and the techniques of washing " dynamiques" or " mechanics.

One can quote in the dynamic techniques of washing: - The centrifugation which proves however insufficient to obtain levels of low turbidity - The floatation which consists in upwards involving the particles using a gas, generally after an operation of joining (gelatin) - Filtration on vacuum rotary filter or filter presses generally held for the residue obtained in bottom of tank after washing static

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