Day and night till march 31st, distillers live according to the tempo of theirs stills and  process  called “double chauffe” or “repasse” in french,  i.e two separate heatings, in a special “charentais” copper still. The distillation is a particular moment which appeals to emotional senses of sight and smell :  a sweety temperature near the stills, the slow flow of the eau-de-vie, and the subtle scents diffusing in the air. Only a handful of them feeds theirs boilers with wood as Bertrand de Witasse from Cognac Raison Personnelle in Grande Champagne. He stays with his alambics 24/24h for two months. Like a solo race around the world ! 

Since the beginning of cognac story, the distillation is still the same with this special double process of heating. The process clearly detailed in this video from BNIC (coordination and decision-making body for the Cognac industry).