GREAT wine only comes from a great site. The curious reality is that despite over 2,000 years of wine-growing experience, the potential of some of the greatest sites in southern France is only now becoming clear.

Once the quality of the site, its soil and climate become clear, it’s then a matter of growing the right varieties in the right way.

One big reason why the true greatness of some sites has been hidden is they’ve been planted with grapes intended for quantity rather than quality.

This was the case at Mas Belles Eaux, a superb vineyard near Caux in the heart of the Languedoc. Between 2002 and 2008 the old vineyards of Mas Belles Eaux and its neighbour Mas Sainte Hélène were snapped up by Christian Seely, the English director of the wine estates owned by French insurance firm AXA.

The vineyards had been used to produce grapes for bulk wines sold through the local co-operative, but Seely and his team quickly realised that they could make something far, far better.

He said: “We believe that, in the future, the Languedoc will be recognised as the source of some of the greatest wines of France and we are sure that Mas Belles Eaux will be among them.”

I visited Mas Belles Eaux in the company of Cédric Loiseau, its technical director, on a blustery day, just as the last autumn leaves were finally falling.

Seely is a canny businessman, but he recognises that Mas Belles Eaux will only achieve great things if money is invested there wisely.

Some of the vineyards have had to be replanted with more suitable varieties, others have had to be re-structured so that the vines can be coaxed into producing better, more concentrated fruit.

Some vines could be left but could be changed to a better variety by the technique of field grafting.

“It works well. You only lose one year’s crop, and after 10 years there is no re-appearance of grapes from the previous variety,” Cédric told me.

More money was spent two years ago on installing a highly sophisticated irrigation system.

“We irrigate around 40 hectares of vineyards here,” Cédric said. “We see it as an essential tool to achieve quality rather than quantity.

“The big problem here is water stress.

“In the 2011 and 2012 seasons, for example, we had virtually no rain between May and October.”

The genius of the new system is that nothing is left to chance. Five permanent probes measure the humidity of the soil, which Cédric is able to monitor at any time by means of a phone app.

The rules for the appellation limit the use of water, but the ability to intervene at the right time makes all the difference.

“You can see the grapes change,” Cédric enthused.

Work began to modernise and improve the winery in 2008. But even a property with all the resources of AXA behind it has to watch the pennies.

Stainless steel fermentation and 20,400-litre holding tanks were bought second-hand from top Bordeaux estate Cos d’Estournel.

I hate to imagine the traffic jam as they trundled along the roads across the country. I suspect the transport costs were almost as much as that of the tanks themselves.

Another illustration that simply throwing money at a project will not guarantee the production of fine wine is the absence of new oak barrels at Mas Belles Eaux.

Instead, second or third-fill casks can be bought cheaply from one of AXA’s Bordeaux estates and then sold on again after a couple of years.

Cédric’s winemaking skill and attention to detail were soon apparent as we began to taste, beginning with samples drawn from the tanks or siphoned out of small wooden casks. Everything has been carefully thought through, with different procedures adapted to bring out the best from each grape variety.

Great wine may only come from a great site, but it is always made by great people.

Quality at Mas Belles Eaux is already abundantly evident in the glass. The difficult, late-ripening Mourvédre does particularly well.

The 2008, for example, is a great success in a tricky vintage. It’s very spicy and rich, with perfumed black fruit and a perfect balance between juicy acidity and melting ripe tannins.

It shows that southern wines don’t have to be blockbusters to impress, elegance is possible too.

A blend of Syrah, Grenache and Mourvèdre, Les Coteaux is the standard bearer of the estate. I tasted every vintage from 2007 and 2011 and, good as each wine is, there’s a steady improvement from year to year. It’s good news. It means that all the hard work and investment of time and energy as well as money is paying off and Seely’s vision of greatness at Mas Belles Eaux is getting closer.

Sadly, the only vintage currently available in the UK is the 2008, a lovely scented red wine, with freshness, elegance and a lingering savoury quality. It costs just £11.95 (from www.vineyardsdirect.com). As the reputation of the estate rises, so surely will the price.

If you happen to be on holiday in the South of France during the summer, the vineyard is open for cellar-door sales, more accurately from a lovingly renovated orangery, where Cédric and his team also offer tapas and wine by the glass every Wednesday evening from June to September. It’s best to book: www.mas-belleseaux.com

We believe that the Languedoc will be recognised as the source of some of the greatest wines of France