Category: How to make Cognac

Cognac must be distilled between the range of 67–72 degrees and many producers will try and get it to the higher end of the range to maximise on the purity of the distillate. Whatever the strength of the vapours, the temperature is quite likely to be very hot and the vapour will rise quickly from the boiler to the chapiteau, the onion shaped pot on top of the boiler. The smaller the chapiteau, the more efficiently the wine vapours are carried on up to the col de cygnet (swans neck). The shorter the col de cygnet, the less spirit will be rectified before it goes round the top bend – at which point it will start to condense as it passes back through the super heater or chauffe-vin, this time to cool the spirit rather than to heat the wine. The final stage of bringing the vapour back to a liquid is through a large condenser with huge coils in a water filled tank , cooling it to a level where it can be tasted by the distiller to judge the quality of the distillation and where the strength can be measured.

The final eau de vie or water of life, a water clear liquid is, once the burnt heads are removed, diverted into a new oak barrel.

Cognac Barrels

Typically barrels are made from oak from the Limousin Forests, some 70 km to the east of the town of Cognac. This has not always been the case though. During the 17^th and early 18^th centuries other woods were used, since travel was more difficult and transporting heavy timber arduous. There is some evidence to suggest that elm or possibly even ash may have been used from the local forest which would account partly for the dry hazel nut taste of very early cognacs. These timbers would never have been highly successful, as the grain in elm is neither straight or easy to bend and oak would even in early days have been preferred.

It is the Forests of Limousin, to the east of Angoulême, that was the predominant reason for the success of Cognac. The trees grow large and thick and the wood is relatively porous allowing both physical and chemical processes to occur in the brandies. Oak from the forest of Tronçais near Burgundy is also used, but the grain is much tighter and the maturing process is considerably increased. However, it suits some houses who seek to develop their cognacs for shorter periods, since the wood contains more lignin and less tannins than Limousin.

Physically, oak is hard, supple and watertight, making it ideal for storage and transportation, but it is also dense, thus allowing only slow evaporation. Wood for the barrels has to be carefully chosen, ensuring that it is free from knots and imperfections. The wood comes from old trees, greater than 50 years old and the staves are split rather than cut to ensure the grain is straight. The staves are air dried outside for about six years before being taken and shaped into curved staves and formed into barrels. Sun and rain remove many of the soluble elements in the wood, including the bitter tannins which would introduce bitterness into the brandy.

Chemically, oak is two thirds neutral and crucially contains little or none of the of the resinous substances found in other woods that can pollute the spirit with undesirable tastes. Like cognac, the actual making of the barrels is a great skill passed down from generations and one that deserves recognition. It can never be mechanised and visiting a cooperage is a memorable experience. Each stave is shaped carefully and then placed together using a metal ring to hold the staves in place. After a complete circle of staves is formed, further rings are added. A groove is then formed at the end of the staves to hold the end plate, held in with pegs. No glue or nails are ever used in the barrels construction.

New oak from either the forests of Limousin or Tronçais contains many harmful chemicals which need to be removed before the brandies are allowed to be placed inside them. The completed barrel cannot be used until it has been toasted to remove some of the harmful wood tannins which can introduce bitterness to the brandy. There is however a small percentage of useful tannins left in the wood and a larger level of Lignins which, when combined with the hemicellulose which makes up most of the rest, gradually dissolves into the maturing spirit, imparting the agreeable sweetness found in older brandies.

The Tannins impart colour to the maturing spirit,  but too much exposure can create a bitter harshness to the brandy. Young brandies are usually only kept in new barrels for perhaps between 6 – 12 months before being transferred to older and mainly neutral barrels, thus creating a more readily drinkable brandy at a younger age. The process of ageing is slow. Naturally the more the brandy comes into contact with the barrel the more effectively it matures, so smaller barriques will tend to provide a better cognac over time than the larger 350 litre barrels. Different variations in the wood, toasting and size of the barrel will change the style of the cognac during its long ageing.

But there is one more ingredient that will provide a major variation in the flavour of the cognac – water, or more significantly the dampness of the cellar in which the cognacs are stored. Many old cellars have earth floors and those closer to the Charente will have a greater degree of dampness than others in the Bois crus. The water molecule is larger than that of spirit, so will block the quick release of the spirits through the wood, allowing more time for the tannins and lignins to dissolve in the spirit, which in the case of brandy aged for 40 or more years will develop the much sought after “rancio”.

The vast majority of distillers in the cognac region are bouilleurs de cru, distillers who grow their own grapes, rather than the bouilleurs de profession, distillers whose sole purpose is to distil the wines for growers and merchants. There are probably nearly a thousand of the former group who sell their brandies under their own name, and it is these whose reputations have developed over the centuries from their family skills.  Of course many of these bouillers de cru also sell their cognacs to a blender, who may keep the cognacs for a few years in casks before selling them in the style of the house or negoçiant  who eventually sell the products in the market.

Distillers all operate under the same strict rules. The wines have to be distilled twice to a maximum strength of not greater than 72 percent, in copper stills with heads that are shaped rather like onions. The distillation must be in two boilings, with the second one not exceeding 25 hectolitres of liquid. Distillation starts in late November and must be completed by 31^st March the following year.

The basic design of the alembic charentais was perfected by the Dutch in the 17^th century and it has not changed significantly since then. The basis of the operation is to gently heat the wine to a very high temperature, which makes it evaporate. The very essence of the wine is collected in the head of the still, escapes through a long curved pipe in the top where it runs through a condenser and returns to a liquid. Control of the process is of vital importance – it must not be allowed to get too hot. In the early days distillation was difficult to control, since wood from the local forests, even coal was used for heating.

Today most stills are heated by natural gas. Oil fire boilers are not allowed as there is risk of contamination from the oil and its residue. Modern distillation has not changed significantly over the years, but control of the process is now much better understood and the various stages at which chemical changes occur can be controlled accurately, thus minimising waste. Whilst there are many standardised practices, the distiller does have a considerable number of choices available that can influence the style and flavour of the final product.

Most distillation in Cognac evolves around the ugni blanc grape and assuming this is a standard factor (it is not always), the first choice is the size and shape of the still and the still head. On the second distillation, the maximum quantity brouillis allowed in the boiler is 25 hectolitres, however 12 and 15 hectolitre stills are indeed quite common, especially amongst the smaller distillers. Many small firms believe, with some justification, that the flavour can be improved when smaller quantities are heated. A crucial factor though, is the design of the head or chapiteau. This collects the vapours from the boiled wine before escaping through the “swans neck”, the col de cygnet. It is then be condensed in cooled coils, the serpentin, where the vapours condense into liquid.

In order to extract the fuller flavours from the wines it is desirable to minimise the levels of rectification. Rectification is when the vapours that have condensed in the still head drip back to be re-boiled, thus neutralising the spirit to a greater extent. A straighter sided head will allow more vapours to pass uninterrupted. A further factor which can influence rectification is the height of the swans neck – the shorter the distance the vapour travels before it is condensed and collected in the barrel, the more flavour will be present in the final eau de vie. It is this process, with lower rectification levels, that the big houses who buy from hundreds of producers for blending, are trying to stop, thus encouraging spirit neutrality to make it easier to blend.

There are many variations allowed in the distillation process which can affect the final quality and taste of the cognacs. One of the areas of modern methods is the argument relating to the use of the chauffe-vin, a simple pot sitting between the boiler and the condenser. Most modern distilleries do use this form of pre-heating the wine before it enters the boiler. The heating is provided by the hot spirit as it passes through pipes which pass through the pre-heater. There is a danger of the wines becoming oxidised if they get too hot and it is sometimes argued that purity is greater if the chauffe-vin is not used.

Perhaps the greatest influence on taste is created by the use of the lees, the mushy solid content of the grapes, which provide the fruitiness from the yeast found in the lees. The yeasts form a number of esters which tend to enrich the final product, and many distillers use this process when trying to develop greater individuality in their cognacs. The practice of distilling on the lees is forbidden by some of the big negoçiants, who are seeking greater neutrality to simplify blending with hundreds of other brandies.

Further variations can occur in the cooking time of the wines, which can be as great as 6 to 12 hours, depending on the size of the still and the heating process. The slower the cooking the more thoroughly the essential qualities of the fruit are extracted. This occurs most effectively in the first distillation, which concentrates the wine approximately 3 to 4 times to produce a brouillis at a strength of around 27-30%. Whilst this is a small variation, it can create a huge difference in the taste! It is in this first distillation that most of the important chemical reactions take place.

The final distillation is required to be between 67 and 72 degrees. The first vapours are too strong and they are set aside from the main part of the distillation, the final vapours are too weak and are added back into the still for re-boiling.

To visit the Charente in October is one of the most exciting periods of the whole of the Cognac season. There is a huge sense of anticipation – vats and stills are being cleaned, machinery is being serviced and viticulturists are checking the acidity and sugar levels in the grapes. They are also making final checks on the quality and cleanliness of the grapes, ensuring that no mildew or rot exists in the clusters of Ugni Blanc, Colombard or Folle Blanche before they are picked.

On the chosen day, usually at the end of October, and depending on acidity and sugar levels, the whole region will go into action and the mechanical harvesters will work down the lines of grapes, plucking the clusters from the vines. The grapes will be loaded into trucks and taken as quickly as possible to the presses. It is essential that they are crushed as quickly as possible to prevent sulphur dioxide forming on the skins as a result of warm weather and natural sugars in the grapes. Modern presses are long rotating cylinders with slatted sides. Two stainless steel plates move in from the ends as the drums rotate, releasing the juice until the pulp of the grape comes out. This is the lees and is sometimes used in the wine to produce a fruitier flavour.

Generally the juice will take about 6-8 weeks before natural fermentation turns it into a wine with an alcohol content of around 8-9%. Around 95% of the wines are made from the Ugni Blanc grapes, but some specialist houses still like the charming qualities of the Colombard and the traditional Folle, which can produce more peachy flavours in the finished cognacs. The wine is a cloudy liquid with a relatively acidic quality, ideal for distilling. It is usually stored in big concrete tanks before being checked for the optimum quality and pumped into the stills boiler for the heating and reduction process.

Legally the Cognaçais can use a number of grape varieties, although the choice is largely theoretical. The Ugni Blanc accounts for over 90% of the total area, with the rest being Folle Blanche and Colombard. Cognacs rise to fame was based on two varieties – the Folle (later known as the Folle Blanche), and the Balzac, both of which were despised by local wine makers. In the 18^th Century the Colombard, which made sweet wines from the Borderies cru, also rose to prominence. Today the Colombard’s inclusion in modern cognacs is limited, as it finishes very short and fails to last on the palate, as opposed to the best cognacs with their great depth and finish.

The Folle Blanche prospered during the 18^th & 19^th centuries. The wine it produced was so acid as to be virtually undrinkable, but was ideal for making cognac. After the Phylloxera it was found that when grafted onto the American rootstock it flourished too vigorously. The bunches were too tightly packed and the grapes in the middle were susceptible to grey rot which could not be accessed with sprays.

So the Ugni Blanc triumphed. As the name implies, it was originally an Italian variety, the Trebiano Toscano from the hills of the Emilia Romagna  near Piacenza. In France it is the most widely planted vine, but it’s popularity is in marked contrast to it’s quality making a highly acidic and short wine (ideal or course for distillation). The vines were pruned hard to reduce yields, but with improved viticultural techniques yields have risen sharply. Even with a high level of regulation by the BNIC, 8 hectolitres of pure alcohol per hectare are produced every year, and most growers could increase on this by up to 50%. There are problems though – the grapes ripen late and produce a weak wine. In hot summers they run the risk of becoming too rich, with strengths of up to 12% making flabby cognac, as was the case in the 1989 vintages.

Finding a more suitable position to make cognac is impossible, since the combination of climate, soil and position creates that lovely French Term, “Terroir”, to which we have no singular description that encompasses such a wide term. The cognac region is in the northern end of the Langue d’Oc, midway between the Bay of Biscay and the Massif Central, a part of France which, when entering from the region just south of Poitier, it is said that the temperature rises 5 degrees.

Winters are usually warmer than more northerly regions and the summer temperatures tend to be less aggressive, providing a climate not hot or dry enough to cause problems with the vines. The quality of the fruit and the intensity of its taste depend on it not being able to grow too prolifically, a factor that is crucial to the quality of the grapes and consequently the wines and spirits produced by them. The balance between the warm sea breezes from the west and the more extreme continental conditions of the Massif Central are at their best surrounding the towns of Cognac and Jarnac. The gently rolling hillsides with their chalky layers rise perhaps no more than 150 metres above sea level, and encourages the perfect maturation of the grapes required for making cognac. Thus the Charente and to a lesser extent Charente Maritime have  over the centuries produced the ideal wines that can be easily reduced in volume by distillation to provide the King of all Brandies, Cognac!

At Brandyclassics we believe very much in education – without it the industry will fail to pass on the benefits of knowledge about potentially most important area of the end customer service. Brandy is important because it creates an opportunity to extend our knowledge of wines. Those who have read our previous notes will understand that brandies are a reduced wine. This series will cover every key aspect of cognac production. Cognac is after all, the “King of all Brandies” and as Samuel Johnson said, “Claret is the liquor for boys, Port for men, but he who aspires to be a hero, must drink brandy”.

During my travels to the finest hotels and restaurants in the world, I never cease to be amazed how little knowledge top sommeliers and bar managers have on this important subject. Let us try and address that problem!

The cognac region is centrally located on the western side of France and the main town is called Cognac. Tthe drink is named after the town and not vice versa. Cognac is about 100 km south east of La Rochelle, which was instrumental in the development of the cognac trade in the 18^th & 17^th Centuries. The other great brandies of France are also made on the western side of the country. To the north is Normandy, from which comes the cidre brandy, Calvados and to the south in Gascogne is the home of Armagnac. But we will concentrate on cognac in this series.