Definition: Cold stabilisation (of champagne)

1) The prolonged stabilisation of wine at a temperature close to freezing point. This must be carried out on wine that has been clarified and improved by adding finely ground tartar crystals, which act as an accelerator in the crystallisation process. It takes place in four phases: First, the temperature of the wine is lowered to its freezing point using refrigeration and a heat exchanger. The wine is then kept at a low temperature in insulated vats for six to eight days. Next, the wine is filtered at the tank outlet at a minimum temperature to prevent the potassium bitartrate crystals from dissolving again. After filtration, the stabilised wine is reheated by passing it through the heat exchanger with a new batch of wine to be treated. This causes a heat exchange between the two wines.

2) Stabilisation by contact. This is a rapid process that combines the action of cold and crystalline germs, maintaining contact between the tartar and the wine for one to four hours with constant agitation. It does not require any negative temperatures.

3) Continuous stabilisation caused by cold and contact with crystalline germs and carried out in continuously operating equipment. The wine is placed in a stabilisation tank and brought to near freezing point, where it is continuously stirred and brought into contact with its own potassium bitartrate crystals for around ten minutes. It is then filtered and sent to the heat exchanger. In some devices, if the wine is brought below its freezing point, the ice accelerates the crystallisation process.

Although each of the processes we have just described gives satisfactory results, the cellar master must always ensure that the wine is properly clarified and cooled to the desired temperatures for the necessary amount of time. The results obtained must be checked to avoid any alterations such as oxidation, degassing or precipitation of colouring matter. Natural fermentation has transformed the sugars in the grape juice into alcohol. The must from each grape variety and vintage thus transformed into wine has been clarified and racked and, after three months, has a beautiful golden colour. After blending these wines, the cuvée is ready to undergo a new stage, which will take place in the most appropriate space for its full development: the bottle or magnum.