(Jamestown-AFP) - Most coffee snobs can only dream of sipping on a brew made from Saint Helena beans.

Imported from Yemen in the 18th century, the tiny South Atlantic island's green-tipped Bourbon Arabica coffee plant produces some of the world's most expensive -- and most delectable -- beans.

St Helena coffee's most famous fan was French emperor Napoleon, who said it was "the only good thing" about living in exile in a rat-infested house on the island for six years until his death in 1821.

The sheer remoteness of the far-flung British island -- stranded between South America and Africa -- has preserved the genetic heritage of the coffee planted by the East India Company, the English trading company, almost 300 years ago.

But good luck getting your hands on the beans, which have become scarce after years of neglect.

Coffee groves on the island, which has a varied climate despite being on the equator, were left deserted until some enthusiasts started cultivating the crop again in the 1990s.

That renaissance was short-lived. The main producer went bankrupt, even after putting the beans on sale in London's exclusive Harrods store.

Then in 2009, Solomon & Company -- a public company known as Solomons on the island -- took over and breathed new life into the Bamboo Hedge plantation.

Cottage industry

"It had become overgrown and there was die-back on many of the trees," said Mandy Peters, Solomons' executive director.

"We have been slowly rebuilding the plantation."

Still, the organic beans are in short supply.

Solomons produces between one and 1.5 tonnes a year, a tiny amount considering world coffee production was about 8.5 million tonnes in 2014.

"This coffee has a superb fragrant bouquet with no off flavours and pleasant floral fruity hints of citrus and caramel strongly hinting of its Yemeni origins," gushes a St Helena coffee importer's website.

All of Solomons' beans are directly exported to England before roasting.

"Our market is global but the quantities are tiny," said Peter de Bruyne, director of British importer St Helena Trading.

"For example, the harvest this year is 200 kilos (440 pounds), which does not take us very far," he added.

The rare beans have fans in independent coffee roasters and dealers in the European Union, Russia, Japan, the United States, South Korea and Taiwan.

Online retailers list the cost of 50 grams (almost two ounces) at £10 (14 euros, $15), and 125 grams at £21, shipping not included.

On the island, where shops stock beans made by small-scale producers, 125 grams sell for £6.75.

Bill Bolton runs a cafe near the port of Jamestown, the capital of the island, where he sells his own coffee.

"It's a hobby really," said Bolton, 74, from Britain, visiting his small plantation. He produces less than 400 kilos of coffee a year.

"It's very slow and laborious, everything is done by hand," said Bolton, explaining that he trims the trees and harvests the red berries in the southern hemisphere summer.

Then, he cleans the beans, dries them in the sun and roasts them in his garage.

His neighbour also makes and sells coffee to a souvenir shop in Jamestown, while the fourth producer on the island, an hotelier, serves the coffee exclusively to his guests.

All the coffee on St Helena is organic, even though it is not certified as such.

With the introduction of weekly flights to St Helena in February 2016 -- replacing an arduous 10-day return journey by boat -- the coffee producers hope they can scale up production, and Solomons is developing two new crop plantations.

"We hope for at least three to five tonnes per year if all goes well, and we have possible expansion plans for the future too," Peters said.