Det verkar inte vara någon teknisk skillnad vad jag kan förstå. Mest geografisk.
Det här hittade jag på nätet. Det är översatt med Google translate
The Charentais still:
is based on the principle of double distillation (alcohol is obtained in two heaters) and water spirits as an average of 72 ° to the output of the still,
The Armagnac still:
is based on the principle of continuous distillation and water spirits as between 54 and 60 ° at the output of the still.
eau-de-vie from the Cognac region is aged in a f t of oak from the Limousin or Tron? ais essentially (capacity from 270 to 450 liters), water-of-life the area Armagnac is aged in a f t of oak from 400 to 430 liters oak mainly from the Monlezun forest in the Bas Armagnac.
The difference is mainly geographical.
Cognac is made from Poitou Charentes while Armagnac comes from Midi Pyrénées and Aquitaine.
Otherwise, grape varieties, production in 2 distillations, assembly and aging are almost identical.
They come from different grape varieties.
The chemical composition.