The taste and colour of cognac comes from the oak barrel

The pleasure of an afternoon can be a glass of good cognac. We savor it with pleasure, warming the glass in the palm of our hand to enjoy its flavors as much as possible. I have often wondered where those special flavors come from because it too is, isn't it, just another wine distillate like many others. And yet so different! In trying to find out the secret, I discovered that what makes the difference, not only between cognac and other wine distillates, but also between the different brands of cognac, is the oak barrel.

In fact, the name cognac is misused. The generic name for white wine distillate aged in oak casks is brandy. Cognac is the name for that brandy made from grapes from the Cognac region of France, distilled in the same region from November to March each year. Distillation takes place in 2 stages. In the first stage, after 12 hours of distillation of the white wine in copper pots, a liquid with an alcohol content of 30% is obtained. In the second stage, after another 12 hours of distillation, a liquid with an alcohol content of 70% is obtained, called eau-de-vie (water of life) by the French. This distillate is aged for at least 2 years in oak barrels carefully selected from the forests of France. It is from this barrel that the cognac takes its specific color and aromas.

The barrels for aging cognac are made only with oak from 2 specific forests in France, Troncais and Limousin. The species used are Quercus pedunculata and Quercus sessiliflora, because they are hard but at the same time flexible. The oak in the Troincais is less hard and the pores are medium in number and size. Limousin oak is harder, with pores of medium size but more numerous. Distillates apparently extract more tannins from Limousin oak, which is why it is the most expensive barrel wood in the world. Cognac kept in such casks is strong, with a balanced taste and fine vanilla flavors.

Barrel makers in the Cognac region have handed down their craft and techniques from generation to generation. Their barrels are always made following the same methods and using wood chosen according to the same criteria, improvisation is not accepted. They know how to choose the best wood and for this they are very well paid by renowned cognac producers.

The oak chosen to make the barrels must be at least 100 years old. Once cut, it is split into planks and left to dry naturally for 1 to 3 years. During this time the tannins that give the bitter taste are lost. It is then cut into standardized-sized planks (doage) with which the barrels are formed.

The most important operation is the burning. The planks, placed around a butt and secured with a metal band to prevent them from spreading, are placed over a fire made of sawdust and pieces of oak wood. The burning time and the intensity of the surface burning of the planks will determine the future taste of the cognac. During burning, tannins are transformed into flavoring substances such as vanillin. We have also talked about this process in the article on wine barrel.

After firing and repeated sprinkling with water to allow for bending, the staves are fitted together with the other bottom to form the barrel. No nails or rivets are used during assembly.

For aging, the cognac is generally put into new barrels to get all the necessary flavors, then moved to old barrels so that the exchange of tannins between the distillate and the wood is reduced. Through the pores of the wood, the distillate loses between 1 and 2.5 degrees/year, but also some water. The loss depends on the place of storage and the conditions in the cellar. In France this loss is called the "angels' share". Calculations show that the angels take a not inconsiderable share. For example, a cognac aged for 50 years in barrels with a loss rate of 2.5%/year goes from 350 liters to 100 liters.

The difference in taste between the different brands of cognac comes from the way the barrel wood is burned and the combination of the length of time the distillate is aged in new or old barrels. It is also from these barrels that cognac gets its beautiful brown color.

Whether you like cognac or not, I hope you enjoyed this French story of the slow transformation of the water of life into cognac, an occasion that the angels also enjoy, having their share.