Driving through the fields of Cognac on a cold day in mid-January, you'd be forgiven for thinking of it as a barren land. Fields and fields, hectares and hectares of spectral, knobbly bare vines scythe through the frost, and the grassy fields are dulled by the grey sky above. But we get a glimpse of what's to come in spring and summer when the low winter sun bursts through the clouds. In an instant, the blue-grey of the vineyards and fields become verdant, the landscape becomes bucolic, and it becomes clear that, within a few months, there'll be fruit and leaves on these vines.

As our car rolls through the undulating hills of this region in western France – about 45 minutes from Bordeaux and peppered with many towns and villages – calling cards of the spirit that takes its name are everywhere. Houses, showing the wear and tear of hundreds of years' worth of the swings in temperature that makes this such a perfect environment for a barrel-aged spirit, bear signs of boutique cognac brands being distilled in the house or garage; vineyards are everywhere – largely ugni blanc, known in Italy as trebbiano; and small white bags on top of the vines indicate the first plantings of the year.

Sometimes thought of as a Christmas spirit, or something to sip in front of a crackling fire, cognac is finally showing signs of being brought into the drinking conversation in terms similar to world whisky. As it should, because this is a complex, exciting drink, born of tradition and manifold history, which has been perfected over hundreds of years. And as provenance and telling the story behind a drink are pulled into sharp focus by consumer desire, buying trends and the bar industry, cognac holds its own. Cognac – often called a brandy but more specifically an aged eau de vie – is not just a luxury product but a way of life here. The abundant vineyards, cooperages and well-stocked bars in even the smallest restaurants in the region are testament to that.

I'm in Cognac with two London bartenders, both eager to learn the story behind a drink that's becoming more prominent in the world of mixing drinks, to see four very distinct houses. The first is ABK6, owned by Domaines Francis Abecassis, which also owns Cognac Leyrat and Réviseur. As we pull in, it's clear this isn't a boutique operation; in fact it's a fully integrated single estate, meaning it owns all of its vineyards, as well as the distillery and the cellars where its products go from grapes to the finished spirit.

The ABK6 brand is the newest, and is the type that's pushing cognac into the glasses of an ever-younger audience. It's apparently named after Francois Abecassis's daughter's text-message sign-off (try saying the letters and numbers in French and you'll get it) and it's a fittingly new-school operation. Gleaming stainless-steel vats connect to underground pipes in the distillery, and in the state-of-the-art winemaking room, 26 tanks vinify the ugni blanc grapes into a high-acidity, low-sugar wine (around 10% ABV), before it's twice-distilled, aged in wooden vats for six months, then laid to rest in smaller barrels of new oak.

ABK6 is apparently named after the owner's daughter's text-message sign-off

In the tasting room, we make our way through a line-up of Leyrat VSOP, ABK6 VSOP and Réviseur VSOP, as well as Leyrat's XO Elite expression and Réviseur's XO, too. Differences between ages are evident: in general terms, younger cognacs retain more fresh-fruit characters that are more instantly evident on the palate, while older ones – due to longer time spent in contact with the oak – mellow out in terms of fruit and develop longer finishes, with more complex flavours of dried fruits and spices showing through. The Leyrat VSOP, for instance, bursts with banana, fresh peach, some floral notes and even a bit of coconut flavour; while the XO Elite (made from a blend of eaux de vies between 25 and 40 years old) has more caramel and raisin elements, and a longer-lasting, more complex finish.

A single-estate producer, though, only tells part of the story of this product. We head to a historic house by the river Charente in the quaint, beautiful town of Jarnac to immerse ourselves in the world of Courvoisier. While its bottle and label are known around the world (chances are you'd recognise it even if you didn't know the specifics of cognac itself, much like Hennessy), and the story of its creation is as much a story of cognac as a whole, and of France, too. It's said to have been Napoleon's cognac of choice, and it was served at the opening of the Eiffel Tower in 1889. It was also a key player in the creation of the Cognac appellation – the designation of origin – and contributed to the name cognac being universally used to describe the drink in the early 20th century.

Courvoisier, though, does not own vineyards. Its production is more about buying from small-scale growers to make its own eaux de vies, as well as working with growers who distil their own from the grapes they've grown. The brand owns two distillers outright, works with six others, and has around 700 partners. Creating a cognac on this scale, much like many of the large champagne houses, is all about blending for quality and consistency – so that every expression of Courvoisier tastes like it always has, up to the the standards dictated by the company's history, and remains relatively unscathed by the occurrence of a poor harvest on a particular year.

This, of course, means that a crash course in tasting cognacs of different ages and from different regions in its grand tasting room paints the clearest picture possible of the difference between age statements, and between the areas grapes are grown in.

Benoit de Sutter, the man in charge of buying the aged eaux de vies, takes us through a tasting. The VS expression (the youngest) is made with eaux de vies distilled from wines not aged on the lees (the yeast used for fermentation) for maximum fresh-fruit flavour and less creaminess, and can be made with grapes grown in Fins Bois, generally speaking the lower end of the quality scale. Borderies, Petite Champagne and Grande Champagne vineyards respectively are a walk up the scale towards the top end, and tend to go in longer-aged expressions. Fine de Champagne is the name given to cognac made only with grapes grown in Petite and Grande Champagne, and is thought of as the only blend with enough character in the fruit to hold its own when aged up to 50 years. There are, it seems, a lot of factors at play here.

this is not just a luxury product to the people of cognac – it's a way of life

We try unaged eaux de vie, a floral, cut-grass-tasting spirit, light in body, not hugely dissimilar to pisco, similarly distilled from grapes. Two-years-aged has a little brown colour from the barrel and a big hit of vanilla (from the wood's sweet sap), while at four years, almond and nut notes show through. At six, there's some festive spice (cinnamon and cloves), while a jump to 15 years provides a full range of Christmas cake flavour. At 25 years it's noticeably richer and more intense, with candied orange and dried plum flavour.

For Courvoisier, it's not only the grapes, wines and eaux de vies that are traded. The brand also sources wood from Dordogne, splits it along the grain, cuts it to size and sends it to the Doreau cooperage. The barrel-making process is a muscular one, and the cooperage is full of fire, hammer banging, steam escaping, wooden staves being bent and stretched into watertight barrels, before being toasted on the inside, finished and sent to producers for ageing.

If Courvoisier's cognacs are a measure of consistency, Hine, an almost literal stone's throw away in a small townhouse just by the river in Jarnac, is the opposite. While the house's VSOP and XO expressions (it doesn't make a VS) are made to broadly the same style year-on-year, they're all designed to bring the best out of the fruit and impart the terroir of the vineyard. Hine is one of the few houses, and the only mainstream one, that regularly releases vintage cognacs, commemorating special years and bountiful harvests with limited-edition runs designed to retain as much of the grapes' character as possible. The brand also releases single-region and single-cask bottlings, too.

Hine, founded by Englishman Thomas Hine in 1763, is made with grapes sourced only in Petite Champagne and Grande Champagne. It owns 70 hectares of vineyards, which provides around a third of its grapes, and works with producers in both regions to buy grapes, wines and eaux de vies, too. The Rare VSOP, aged for an average of eight years, is its flagship, while its XO is around 22 on average. The Triomphe XO blend is around 40.

But in the face of all this tradition, it, too, is modernising: the single-cask and vintage expressions might be aimed towards cognac fiends, but its H by Hine bottling, a snip of the price of a long-aged expression, is aimed firmly at the bar trade and home mixologists. At around the price of a decent bottle of bourbon, it's a way of convincing people to challenge their perception of the drink. As the brand's ambassador (at the time of my visit) Marie Emmanuelle Febvret says, "People think it's strong, it can't be mixed, it's expensive – all of this can be proven wrong."

Patrice Piveteau, Frapin's cellar master, noses a glass of the house's cognac

WHAT'S IN A NAME

A guide to age statements

VS

VS stands for Very Special – a slight contradiction in terms seeing as a VS cognac is the youngest and therefore usually the most approachably priced. These cognacs are made with a blend of eaux de vies aged for a minimum of two years.

VSOP

Very Superior Old Pale is a little older – a blend of eaux de vies the youngest of which have spent at least four years in the cask, although the average is often older than that.

XO

Alarmingly like text speak for a centuries-old designation, XO stands for Extra Old – at least six years for the youngest eau de vie in the blend.

Napoleon

Napoleon is an expression started by Courvoisier that has spread to other houses, too. In basic terms it's an  XO, but the average age tends to  be around 20 years.

Paradis and Hors d'Age

Cognacs tend to stop developing flavours and are at risk of too much oxidation much beyond 50 years, so after that they're stored in Paradis cellars in containers called demijohns. Cognacs marked as Paradis or Hors d'Age can contain eaux de vies of 100 years or older.

 

Our last visit is to Frapin, a single-estate house that uses only Grande Champagne. To give you a sense of the reverence with which it treats its spirit, it's also a parfumier, making fragrances inspired by cognac (which makes sense, when you think about it – the spiciness of wood mixed with lighter-end botanical notes). It also ages its cognacs longer than the minimum required by the appelation, so its VS could technically be a VSOP. And in 2008, it won the ISC Best Spirit in the World prize – the first ever time the winner wasn't a whisky.

We walk around the blending cellar, designed by Gustave Eiffel, and the dusty cellars, too, and in an historic-feeling tasting room, we taste many of its expressions. They're complex, delicious, and the older expressions give a firm reason for their reverential treatment: the Extra is ridiculously smooth and well-rounded, the VIP XO is full of butter, vanilla and coconut. We even try the 1888, made largely with blends around 60 years old, and one from 1870.

Four very different houses have painted a multi-faceted picture of what is clearly an incredibly nuanced spirit. And, after tasting myriad different varieties of different styles, I finish the trip at my hotel bar. The rack, as with every restaurant or bar I've stepped in since I've been in the region, has a huge selection of cognac, and we experiment with cocktails – a cognac old fashioned and manhattan, and of course the sazerac, which can be made with rye whisky, cognac or both. It compliments the sharper spice notes of the spirit with its absinthe wash and the warmer ones with its bitters. It's not sacrilege to mix cognac; just as with a perfectly made old fashioned with a bourbon, it can elevate the spirit, and turn it into a totally different proposition.

The two bartenders with me agree. This spirit is one whose sometimes austere heritage hasn't hampered its ability to capture the attention of the bar trade or of drinkers. And with interest in dark spirits continuing to grow, there might not be a better time to start discovering.

As for the people of Cognac, who'll spark into life when the first leaves start appearing on those bony vines, this somewhat insular culture of cognac-making won't remain in the dark. Just as that sun pokes through the winter clouds and transforms the landscape in a snap, a light's starting to be shone on this inventive, beautiful spirit.

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