Other than sandcastles, it’s generally inadvisable to build things on sand. It’s pretty much the exact opposite of a solid foundation. Building on sand is like drinking seawater when you’re dehydrated or reading tabloids when you want balanced reporting: a self-defeating exercise.

The viticultural equivalent can be found on the Portuguese coast near Lisbon. Colares is a wine region whose vineyards are pure sand. There’s no trellising or training here, just withered branches snaking out of the ground and sprawling over the sand like zombified limbs rising from the grave.

Today, there are only around 19 hectares of this vineyard still in existence, compared to almost 2,000 back in the 1930s. Much of the original area has been sold for redevelopment to accommodate Lisbon’s swelling conurbation. Those vineyards that remain are hugely labour intensive.

New vines have to be planted in trenches up to 2.5 metres deep to allow the roots access to water, then sand is gradually piled back on top over the following years. During ripening season, the grape bunches must be individually lifted off the ground using large twigs to stop them getting burnt when it’s sunny, or going mouldy when it rains.

However, sand did prove to have one enormous benefit as a vineyard soil, back in the heyday of Colares: it was immune to phylloxera infestation. That meant the region could continue making wine when the rest of Europe could not. At its peak, Colares produced more than one million litres of wine every year. Such enviable success attracted unscrupulous profiteers making fraudulent knock-offs, so in 1938 a draconian law was passed forbidding anyone but the local co-operative cellar from making Colares wine.

Once grafting was discovered as the solution to phylloxera, the decline of Colares was inexorable. Not only was everywhere else able to produce wine more cost-effectively, but latterly the region didn’t qualify for EU grants because it remained planted on its original roots. Lawmakers assumed that all ungrafted vines were susceptible to phylloxera and therefore unworthy of subsidy; Colares was the exception to the rule that suffered as a result.

Making the wine is no less challenging than growing the grapes. Reds are made from the local Ramisco variety, which requires at least five years in ancient casks to tame its ferocious tannin. The result is esoteric and fascinating, a bit like Barolo’s mutant twin.

The story of Colares is tailor-made to appeal to the engaged wine drinker: the terroir is extreme, the history is fascinating and the wine itself is unique.

So why am I telling you this? Because I bet you’ve never heard of Colares. Even if you have, I bet there’s none on your shelves, and even if there is I bet you haven’t sold much recently. Having a great story is an essential part of selling wine, and there are millions to choose from. Making sure you’re telling the right ones to the right customers is the best way to sell wine.