Alcohol is a product of the fermentation of sugars existing in a natural state in the fruits. It is associated with many others made up; it should be isolated from these complex mixtures. This operation is carried out by distillation. The principle of distillation is centered on the differences in volatibility of these various compounds.
The Cognac is obtained by the distillation of the white wines collected in the zone of Label of origin. These wines have a high rate of acidity and are not very alcoholic.

Distillation is carried out in two " heatings ", by means of a still, known as " Charentais ", composed of a characteristic boiler of the shape, heated with naked fire and surmounted by a capital in the shape of head of maure, olive or onion, prolonged by a swan neck being transformed into serpentine and crossing a basin cooling called " pipe ".
The wine not filtered is introduced into the boiler and is carried to boiling. The alcoholic vapor gets clear, accumulates in the capital, engages in the swan neck then in the serpentine. In contact with the cooling agent, they condense to run out in the form of "brouillis".

This slightly turbid liquid, titrating from 28 to 30 % vol., is versed in the boiler for one second distilation, it is " good heating ". For this second heating, the capacity of the boiler should not exceed 30 hectolitres and the volume of the load is limited to 25 hectolitres. The distiller will have to then proceed to a delicate operation called " the cut ": the vapor which arrives the first, very rich in alcohol, is appelèes the " heads ", and isolated (it account for only 1 to 2% of volume). Comes then the " heart ", clear and limpid brandy (average maximun: 72%vol.) who will give the cognac. Lastly, the distiller eliminates the " seconds " or "tails" when the alcohol meter indicates 60% flight. "Heads" and "tails" are redistilled with the wine or the "brouillis".


During this double operation, times of run and the temperatures are very supervised. The success of the cycle of distillation, which lasts approximately 24 hours, requires much attention, a constant monitoring and a great practice on behalf of the distiller which also can, while intervening on the techniques of distillation (proportion of fine dregs, recycling of the " seconds " in the wines or "brouilis", temperature...), to confer on the cognac elements of its personality.