My guide, Brian, stops the Land Rover and points into the forest. "Voila. La vanille."
We get out of the vehicle. Dense tropical vegetation reaches right to the rough track. Beside the track are a number of saplings, and entwined around each one is a pale green vine with elongated leaves. Brian holds up part of the plant. "There, see? The vanilla flower."
It's pale yellow, with long splayed petals. Its stamen protrudes from the flower's centre. A little further up the vine hangs a bunch of green beans. These are the fruit of the vanilla vine, of the plant known in French Polynesia as "Vanilla tahitensis".
Naturally pollinated by butterflies, the demise of these insects means that the process must now be carried out by hand.
Over a year later, after the mature beans have been picked, dried, sorted and packed into sachets they will be worth about $400 a kilo.
Later, in the little village of Faaha, Brian takes me to a family-operated vanilla production centre. Inside the sales room, spread out on the counter, are dozens of packets of mature vanilla beans. Most hold 10 brown beans, about 13cm long. I pick a packet up and sniff it. The fragrance is alluring. I hand over a 1000 franc note - about $15 - to the elderly woman proprietor.
"Now," Brian suggests, "you buy a bottle of rum, put the beans in the rum and leave them there for six months. After that you will have all the vanilla essence you will need."
We are on the island of Tahaa, one of the Leeward Islands of French Polynesia. Forty minutes' flight time north-west of Tahiti, Tahaa is known as the Vanilla Island, as it produces most of French Polynesia's annual yield of 35 tonnes.
Used mainly as a natural food flavouring, vanilla can be incorporated into everything from rice pudding to ice cream to white sauce to accompany fish dishes.
Its smell is said to calm the nerves. On Tahaa mine don't need soothing, but I keep sniffing the aroma anyway.
The vanilla vine was introduced to Tahiti in 1848, from the Philippines. First grown by Tahitian families, by 1880 vanilla growing was well established, with the local Chinese community heavily involved in its production and marketing.
Production declined in the 20th century, but is now resurgent, with many of the vines now being grown in shade houses. Brian points these out to me as we drive around the island. Rectangular in shape, the shade houses are covered in black, semi-transparent cloth.
"The cloth is very special," Brian explains, "because it lets in just the right amount of sunlight to allow the flowers to bloom and the beans to ripen."
The Land Rover reaches the top of a rise, then Brian drives out on to a grassy ridge. From here are panoramic views of the island and the sounds which deeply indent Tahaa, particularly Haamene Bay, which penetrates almost to the very centre of the island.
Looming above us is Mt Ohiri (598m), the island's highest peak.
An extinct volcano, Tahaa is heart-shaped, with a mountainous core and four bays which deeply indent its southern coast. The island's interior is covered in lush forest and its volcanic soil is rich, giving it a Garden of Eden appearance.
A string of white sand islets - motus - lie on the northern edge of the island's lagoon, from where there are hypnotic views of the soaring profile of Tahaa's northwestern neighbour, the fabled isle of Bora Bora, just 20km away.
Brian - originally from Denmark, a French Foreign Legion veteran, now married to a local woman - extols life on Tahaa. There is no crime on the island, he tells me. Their two children are doing well at the local elementary school.
People don't have to work very hard, because "There's fruit on the trees everywhere, there's heaps of fish in the lagoon."
Brian loves it here. Well he would, I think, after being a French Foreign Legion paratrooper in the Sudan. To emphasise his point Brian leans out the window of the Land Rover, plucks a yellow star fruit from a tree and hands it to me. It's tart, but very juicy.
Above the rough road, a north-facing hillside is covered with grey-green pineapple plants, while between the hillside and the road the land is dense with banana and coconut palms. I've seldom been in such a luxuriant setting.
There is no airport on Tahaa, and although a 70km sealed road encircles the island, much of the traffic goes by water.
Motorboats and ferries from Raiatea, Tahaa's larger neighbouring island just to the south, transport visitors and locals across the two islands' shared lagoon, around the coast and into Tahaa's deep bays.
The island is spectacular, serene, and almost totally uncommercialised. There is no real town here, just a few well-tended villages: Haamene at the head of the longest bay of the same name, Faaha where I bought the vanilla beans, Patio on the north coast and Tapuamu on the west coast.
There is a French-run de luxe resort on one of Tahaa's northern motus, but most visitors stay in one of the island's family-run pensions. This is a great way to get to know some of the locals, and to experience village life.
Tahaa's other prized product is black pearls. Brian takes me to a pearl farm at Faaha Bay, run by the multi-talented Laughlin family.
The Laughlins are descendants of an Irish grandfather and a Tahitian grandmother.
One of the grandsons is a singer, as is a grand-daughter, Sabrina, who just produced her first CD. She also runs the boutique which sells black pearl jewellery, only 100m from the site where the pearls are cultivated, under the direction of her equally good-looking brother, Matahi.
The black-lipped oyster, Pinctada margaritifera, is not native to Tahaa (it comes originally from the lagoons of the Tuamotu archipelago), but it transplants well to the crystalline waters of Faaha Bay.
Matahi shows me a just-opened oyster, about the size of an open hand. And there, tucked into the folds of its black flesh, is a pearl.
Its shape is imperfect, but it's the size of a small marble and has the characteristic lustre of the sea's natural gemstones. The variable colours are part of Pinctada margaritifera's allure: they range from smoky grey to peacock blue to champagne to almost black.
Matahi explains to me the process by which the black pearls - called in Tahitian "poe rava" - are cultivated.
The two halves of the shell are prised open a little with forceps, allowing the insertion of a Mississippi mussel shell bead into the oyster's reproductive organ, and the grafting on to the bead of a piece of the oyster's mantle. This initiates the pearl growth process, but it is a delicate - almost a surgical - process, carried out by skilled Japanese technicians.
The pearl then begins to develop, growing around the nucleus at a rate of about 1mm a year. The shells must also be periodically removed from the water for thorough cleaning.
In the showroom, Sabrina points out the jewellery with pearls as their centrepiece. They are mainly pendants, rings and earrings.
The variety of colours and settings seem infinite, their beauty irresistible, the prices for me, unsustainable.
Brian's launch is tied up to the Laughlin's wharf. He casts off and in minutes we are hurtling down the bay, then out into the encircling lagoon. There, veering right, we head off in the direction of neighbouring Raiatea island, which is half an hour away. All around the crystal-clear water sparkles like champagne.
In minutes Tahaa is behind us, its green mountains appearing to shrivel into the distance.
But memories of this lovely island will take a great deal longer to fade.
Air Tahiti Nui flies from Auckland to Tahiti on Mondays and Fridays, and code-shares with Air NZ on Saturdays and Sundays. Flight time is five hours, 30 minutes. See www.airtahitinui.co.nz.
There is no airport on Tahaa. Visitors fly into Raiatea, Tahaa's sister island, on Air Tahiti, then take a 15-minute transfer to Tahaa by shuttle boat across the lagoon. For Air Tahiti's timetable and fares see www.airtahiti.aero.
Family-run pension accommodation on Tahaa is available near Baie de Haamene, at: Pension Hibiscus, www.tahaa-tahiti.com, Vaipoe, www.infotahiti.com and Tiare's Breeze, www.tiarebreeze.com.
There are three hotels located on Tahaa's islets:
*Graeme Lay travelled to Tahaa and Raiatea as a guest of Tahiti Tourisme and Air Tahiti Nui.