Cognac: Charentais Distillation
Cognac Cognac Elaboration: Distillation
Once alcoholic fermentation is completed, the white wine has to be distilled to make the eau-de-vie.
Distillation
The distillation method has not changed since the birth of Cognac. The special Charentais copper stills “à repasse” that were used then are still in use today. Cognac distillation is performed in a two-stage process:
  • Stage one: a first distillate is obtained, referred to as "brouillis", with an alcohol volume of 28 to 32%.
  • Stage two: The "brouillis" is returned to the boiler for a second heating, known as "la bonne chauffe".


Why is Distillation Necessary?
Alcohol is a product of the fermentation of sugars, found in its natural form in fruit as fructose and glucose. Alcohol is also associated to many other components and must therefore be isolated from them. This operation is performed by distillation. The principle of distillation is based on the volatility differences of these components. In a distilled eau-de-vie we only find those volatile substances that make up the main features of the bouquet.
Which Wines Are Distilled?
Cognac is obtained by the distillation of white wines harvested in the Controlled Appellation area. These wines have a high acidity and a low alcohol content.
A Perfect Still
The Charentais StillDistillation is carried out in two “chauffes”, that is, in two separate heatings, using a special Charentais copper still. It is made of a uniquely shaped boiler heated on a naked flame topped by a still-head in the shape of a turban, an olive, or an onion, and prolonged by a swan-neck tube that turns into a coil and passes through a cooling tank referred to as “the pipe”.
The Distillation Method
Unfiltered wine is poured into the boiler and brought to the boil. Alcohol vapours are freed and collected in the still-head. They then enter the swan-neck and continue into the coil. Upon contact with the coolant, they condense, forming a liquid known as “brouillis”. This slightly cloudy liquid with an alcohol content of 28 to 32 % alcohol is returned to the boiler
for a second distillation, known as the “bonne chauffe”. For this second heating, the boiler capacity must not exceed 30 hectoliters, and the load volume is limited to 25 hectoliters.
The master distiller must then carry out the delicate operation known as “cutting” or “la coupe”:
the first vapours that arrive, called “the heads”, have the highest alcohol content, and are separated from the rest. Then comes “the heart”, a clear spirit that will produce Cognac.

Afterwords the distiller gets rid of “the second cut” when the alcoholometer registers 60%. And finally he eliminates the tails. The “heads” and “second cuts” are redistilled with the next batch of wine or “brouillis”. The success of the distilling cycle, which lasts about 24 hours, lies in the constant supervision it requires and in the extensive experience of the master distiller, who may also intervene in the distillation techniques (proportion of fine lees, recycling of “tails” in batches of wine or “brouillis”, temperature curves…), thus conferring Cognac facets of his personality.



NOTE
The distillation season for white wines destined for the production of Cognac closes on March 31st following the harvest.
The Ambiance of the Charentes
Distilleries work day and night during the winter months. It is a time when the Charentais adapt their lives to the rhythm of the stills, in an atmosphere where the glow of the flames, the quiet bubbling of the alcohol, the water, the copper and the bricks form a marvelous combination.

Charentais Distillation: The Wine PreheaterThe traditional Charentais still is often equipped with an energy-saving wine preheater. This optional device, in which the heat is provided by the alcohol vapours passing through it, preheats the wine that is to be distilled in the next cycle.