Nowhere in France is unknown: it's scarcely a land of surprises. Nevertheless, the journey from Paris to Cognac is less familiar than many. In the 18th century it was one of the routes most travelled by commis voyageurs working the brandy and Bordeaux wine trades. A commis voyageur was – and still is – a commercial traveller, an explorer of new business worlds; it's an invention as distinctively French as cognac itself.
Wondering how cognac became an eponym for brandy, I thought it would be amusing to rediscover the commis voyageur on this route, replicating the journey from the spooky Alphaville-like setting of Paris-Montparnasse station on the TGV to Tarbes, via Poitiers and Angoulême, where you step off the train into a quiet Balzacien backwater.
Honoré de Balzac chose Angoulême as the setting for Les Illusions Perdues (1857) in his great story cycle La Comedie Humaine. Famous only for printworks and papermills,Angoulême recommended itself to Balzac on account of its suffocatingly small-minded provincialism. Disdainful, disparaging, jealous and miserly: those are words Balzac used to describe the local mentality. As my train pulls off in its direction, I suspect traces remain.
I leave Paris early, like a thief in the night... or perhaps a commercial traveller on a mission. First there are inky blue suburban townscapes illuminated by harsh yellow street lights that Magritte would have recognised; a bizarre contrast is established between outside and the bright TGV interior, now looking dated and very le design. Very Roger Tallon and Olivier Mourgue: it's that French style they do so well on autoroutes: mannered, over-confident and urban.
Suddenly, I am in empty France as the TGV rushes towards Poitiers, ploughing-up little disturbances of characteristically provincial French ugliness en route. I note the exceptional number of mournfully hideous houses and electrical installations in Vienne. Or is it Deux-Sèvres? After Poitiers, a lot of places you have never heard of. Couhé? Ruffec? Mansle? The French worry about desertification. Here it is.
I have created a fantasy commis voyageur as a travelling companion to amuse me; he is Yves Tricouleur, an Angoumois who deals in wine and the distinctive eau de vie of Charente. Unlike my air-conditioned whizzing grand projet, his journeys to and from Paris and Cognac would have been 500km of bone-shaking, dusty, cold torment. Leaving the capital by the Porte St-Jacques, his stage-coach was stiffly sprung, had unyielding seats, was likely overcrowded and offered only leather straps for comfort and support. Dr Johnson said: "If I had no duties, and no reference to futurity, I would spend my life in a post-chaise with a pretty woman." Maybe, but Dr Johnson was being fanciful and did not know about high-speed trains. The life of a commis voyageur aboard his coach was a hard and dirty one, but hardships were necessary to set up working commercial networks.
A real-life commis voyageur who did this journey often was Richard Hennessy, an adventurer in Louis XV's Brigade Irlandais army and a cousin of Edmund Burke, who, in 1765, gave his name to Cognac's local eau de vie and created one of the very first modern supply chains and branded products.
From Angoulême, it's about 45km to Cognac itself. They say the closer you get to the town, the more the quality of the brandy improves. But before the tasting that is one of my objectives, there's the strange, silent, open landscape. Notably curious features in this part of France are the Lanternes des Morts: haunting, lonely towers that were the subject of a 1998 monograph by John Gordon Bate called Lanterns for the Dead. You can find the remains of one in Angoulême itself and other noteworthy examples are at Brigueil-le-Chantre, Cellefrouin and Pranzac. Often, they are close to cemeteries. Some say they offer illumination to lost souls. Others argue that "morts" is a peasant's mis-hearing of "Maures", or "Moors": a reminder that, in 732, Arab invaders got as far north as Poitiers before Charles Martel sent them back. Moorish progress was rapid in the 8th century: there is still not a lot in the way hereabouts; as late as 1960, wolves were still hunted in the area.
The brandy-producing area has Cognac at its centre and includes the departments of Charente and Charente-Maritime, as well as bits of Dordogne and Deux-Sèvres. Montguyon is to the south, Angoulême to the east, Royan is just beyond the western edge, while St-Jean-d'Angély is the north. With a French genius for hierarchy combined with pleasant natural accidents, the best quality brandies come from the centre where they are known as Grandes Champagnes. Each successive ring marks a decline in quality: Petites Champagnes, Borderies, Fins Bois, Bons Bois and Bois Ordinaires. Here, "Champagne" has nothing to do with the sparkling wine, but is simply a corruption of the French word for "country" (campagne).
Cognac is on the banks of the Charente, and is a quiet, contained town not perhaps much changed since Richard Hennessy's day. The ambitious reporter looks in vain for artistic or literary associations. A novel called The Voyage by the once popular, but nowadays un-read, Charles Morgan was set here. And that's about it. Although there is a strong regional tradition in cooking, Cognac has no great restaurants to be recommended. Curnonsky and Conil, the two great authorities on French regional food, get terribly excited about the profligacy of milk, cream and butter in the cooking of the area. They sing of mouclade (mussels in butter and flour), la chaudreé (a robust fish stew), friture d'Anguilles (fried eels) and la sauce a l'ail Saintongeaise (garlic, shallots, rabbit's liver, lard, blood and egg yolk – yum), but these are polite fictions.
Instead, Cognac's real business is strong drink. When you look at a Michelin map of any big French city, it's surprising how very much surface area is devoted to hospitals: whole city blocks in the case of Paris. But, in Cognac, that devotion is to the chais: the vast warehouses that store barrels of the precious brandy ready for export. Travellers routinely noted how the presence of brandy encouraged the cultivation of airborne fungi which left Cognac's buildings weirdly blackened, although the combined forces of French tourism and the international luxury goods businesses have cleaned it up somewhat. Cognac is not a particularly charming place, but then nor is Epernay, champagne's epicentre.
Through the magical chemistry of distillation in mighty copper alembics, you get the complicated, headache-making transformation of the nasty, thin green wine that the Ugni Blanc grape – which Italians call Trebbiano – produces in this terroir: cognac. The town is stiff with business and brand names: Camus, Courvoisier, Rémy Martin, Martell and Otard are prominent. But Hennessy shows its dominance of the trade with the biggest chais of them all, straddling the sluggish Charente river. The company founded by our Irish adventurer merged with champagne-maker Moët & Chandon in 1971, which, in turn, merged with Louis Vuitton in 1987 to make LVMH, the planet's dominant luxury-goods conglomerate.
The same Dr Johnson who so enjoyed his poste-chaise pronounced memorably on cognac. "Claret is the liquor for boys; port for men; but he who aspires to be a hero must drink brandy". Since I have that aspiration, I accepted an invitation from Maurice Hennessy, the eighth- generation direct descendant of Richard Hennessy to taste my way through historic layers of his family grog. Maurice occupies that ambassador role that modern luxury businesses require: something between a commis voyageur and global PR. My acceptance was notably heroic, as I do not specially care for the stuff, but Hennessy, an intoxicating mixture of modern French suaverie and residual Irish blarney, is a persuasive tutor.
The cognac process is a mixture of science and art, of vague, but powerful, impressions and detailed, although mysterious, specifications. In the vineyards, delicious wood-smoke. In the distillery, overwhelming alcoholic vapours. The deconstruction of the grape into volatile liquor begins with a rough, murky, milky wine known as brouillis.Undrinkable by today's standards, it was commonplace in the 18th century and popular with Biblical folk. The brouillis is doubly distilled Maurice tells me: "We take from the wine what we love." What they love is the one litre of heady cognac that is the reduction of nine litres of wine.
We work our way through Les Crus du Cognac in ascending order: Bois Communs, Bois Ordinaires, Bons Bois, Fins Bois, Borderies, Petite Champagne and Grande Champagne. In this context, "champagne" means chalky soil.
We sniff and ruminate and consider those tasting absolutes: the primaries and secondaries, clearness, brightness, length and associations. The nose on the best of these is a little like the bouquet du corsage. And the cumulative effect emboldens one to heroism and to mild cognitive confusion: I think I hear "your mouse is full of flavour". But he meant "mouth". Then, there is a sinister reference to "soup liars", perhaps people who tell mischievous untruths about the first course, but in fact he meant trade "suppliers". I can hear a repetitive banging. I am uncertain whether it is the tonnelier making barrels in a distant shed or a destructive cerebral event caused by a misguided pursuit of the heroic.
Then there's a night in the Château de Bagnolet, just out of town on the banks of the Charente. A prim, Empire-style property of 1810 built by a brandy-producing Cognac family called Augier, it was acquired by the Hennessys in 1841. Said to be based on a model in Louisiana, its location is unfeasibly romantic even as it hovers between a private house and a corporate convention centre.
The Château de Bagnolet could be the set for a film of a Balzac heroine, tormented by adulterous anxieties as she drifts, chewing her lip, through the mists in the Jardin d'Anglais or brooding over Byron in the Jardin d'Hiver with its hibiscus and bougainvillea.
But really it is the set of an even more engaging drama. The garden, re-designed at the start of the 20th century, includes a Temple d'Amour, a clear indication of hedonism's claim on the property.
Decoration of the Château includes a good deal of unnerving French Modern Purple, a colour also found in the ageing TGV. The wreception room reminds me of the lobby of the old Jaguar factory in Browns Lane, Coventry: English associations are unavoidable. What it represents is the contemporary French conception of luxury: an elaborate structure of synthetic desire, a fiction as powerful as 19th-century novels or myths about the perfection of French food. In this, there is something elegiac, a sense of the parade passing: delicious, but sad, like cognac itself.
Cognac sales are volatile inEurope, down one year, up the next. Britain is the biggest European market, but no one anticipates significant growth. The future for brandy is in the Far East and the elaborate luxury narrative surrounding cognac exists to create and reinforce demand among Chinese customers who neither know nor care about Irish entrepreneurs, Balzac, romantic walks in the winter garden, or ghostly Saracen monuments in the Saintonge. It is said that French luxury is feminine, while British luxury is masculine; if that is so, it's a fading beauty.
Ambrose Bierce, author of The Devil's Dictionary, deserves the last word on brandy: "A cordial composed of one part thunder-and-lightning, one part remorse, two parts bloody murder, one part death-hell-and-the-grave and four parts clarified Satan. Dose, a headful all the time."
And, since this is my story, I have the last word on Cognac's region and cognac the phenomenon. Honoré de Balzac got to know Angoulême because he was friends with the manager of the town's State Gunpowder Factory, splendidly appropriate given the number of explosive metaphors routinely employed to describe the local brandy's taste and after-effects. Rediscovering the commis voyageur's route from Paris to Cognac is a nice adventure in commercial history. Seeing the thin, unpromising soil of the vineyards and tasting the green wine is a fine introduction to the ingenious alchemy of the distiller's alembic.
Cognac itself? The gardens at the Château de Bagnolet are a perfect exhibition of haut-bourgeois pomp and all its contradictions. The sight of a Lantern of the Dead is a timely reminder of the futility of ambition.
Nowhere in France is unknown, but this is really quite strange. And think of this: someone in Shenzhen who makes plastic ducts for a living is this instant enjoying the branded commodity that is the result of an Irish adventurer's journey into commercial travel 250 years ago.
Travel essentials: Cognac
* Take the Eurostar (08432 186 186; eurostar.com) from London St Pancras, Ashford or Ebbsfleet, then change from Paris Gare du Nord to Paris Montparnasse for direct trains to Angoulême. Local trains to Cognac take around 40 minutes from here (sncf.com).
* Tours of the Quais Hennessy in Cognac (00 33 5 45 35 72 68; hennessy-visites.com) are offered at 10am-11.30am and 2-5pm daily. From October to December and March to April, the tours are only offered on weekdays. Closed January-February. Guided tours start at €9 and should be reserved in advance.
* Chateau de Bagnolet, route des Boutiers, Cognac (00 33 5 45 35 74 74; hennessy.com). The gardens are open to the public once a year, usually in June. Admission free.
* Hotel Heritage, rue d'Angoulême, Cognac (00 33 5 45 82 01 26; hheritage.com). Doubles start at €70, room only.
* Château de l'Yeuse, 65 rue de Bellevue, Châteaubernard, Cognac (00 33 5 45 36 82 60; yeuse.fr). Doubles start at €109, room only.
* Cognac Tourist Office: 00 33 5 45 82 10 71; tourism-cognac.com
Charente Tourism: lacharente.com