Mid-October : The Harvest
Some harvesters continue to harvest by hand, but the great majority now use a harvesting machine. These machines have existed for about 40 years and are perfectly suited to the needs of the region’s growers.
Harvesting may begin as soon as the grape reaches maturity, generally at the beginning of October and conclude at the end of the month.
Pressing and Fermentation: The Natural Method
The grapes are pressed immediately after harvesting in traditional basket plate presses or pneumatic bladder presses. The use of continuous presses is forbidden.
Fermentation of the juice follows immediately. Chaptalization (the addition of sugar) is forbidden by law. Pressing and fermentation are closely supervised, as they have a determining influence on the final quality of the eau-de-vie.
From wine to eau-de-vie
About 5 to 7 days after the beginning of fermentation, the wines for Cognac contain about 9% alcohol.
With their high acidity and low alcohol content, they are perfect for distillation, which must be completed by the next March 31st.
A perfect still
Distillation 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 vapors 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.
Afterwards the distiller gets rid of “the second cut” when the alcoholmeter 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.
Selecting the Wood
Cognac ages exclusively in oak casks traditionally from the Tronçais and Limousin forests – Quersus pedunculata and Quersus sessiliflora, respectively – depending on the producer and style. These two varieties of oak were selected because of their hardness, porosity and extractive characteristics. The Tronçais forest, in Allier, provides softer, finely grained wood, which is particularly porous to alcohol. The Limousin forest produces medium grained wood, harder and even more porous. The tanins in Tronçais oak are famous for their softness, whereas those in Limousin oak are known for the power and balance they communicate to Cognac. An eau-de-vie will extract more tannins when it is aged in casks made with Limousin oak.