Nuts in Sicily by Martin O'Brien

There's an air of expectancy in Sport-Bar Saitta on the corner of Bronte's Piazza Spedalieri. It's late Thursday afternoon and as the day's siesta comes to an end the shutters of this Sicilian hilltown on the western slopes of Mount Etna creak open and the streets start to fill again. Outside on Spedalieri's sloping square the screaming buzz of the first motorinis rents the air as teenagers race their patched-up, souped-up Vespas through Bronte's narrow, lava-cobbled streets. Inside the bar, the men shake their heads and order another espresso, or grappa, or glass of mandorla, the cool, sweet concoction of milk and almonds that's a favourite (non-alcoholic) tipple in these parts. As evening falls, and the Saitta regulars gather, there is only one topic of conversation – the coming weekend's biennial Sagra del Pistacchio, the town's fourteenth Pistachio Festival.

Known throughout Sicily as the Citta del Pistacchio, the Capital of Pistachio, Bronte has been waiting two years for this harvest celebration, the time it takes for the pistachio nut to ripen. Already marquees have been erected along Via le Catania and Via Cavallotti, and around the edges of Piazza Santa Maria del Soccorso and Piazza Giovanni XXIII, ready to be stocked with an abundance of local produce, everything from orange-blossom honey, spiced salamis and pungent cheeses to the work of local artists and artisans – all the usual lurid landscapes and olive wood salad bowls.

But it is Piazza Spedalieri outside Sport-Bar Saitta where the real action will take place, where Bronte's brass band will perform its boisterous oom-pah-pah repertoire, where speeches will be made and prizes given, and where the townspeople will display the real treasures of their harvest festival – towering trays of sweetmeats or dolci, tubs of ice cream and granita, stacks of nougat-like torrone and jars of pesto sauce, everything on the shelves and trestle tables made from the humble pistachio nut that has grown on the lava fields around Bronte since Roman times.

Leaving Sicily's second city, Catania, and heading north-west along the side of the Valle del Simeto it takes less than an hour to reach the first pistachio trees, terraced into stony slopes shaped by the lava flows of Mount Etna and set some eight hundred metres above sea level between Bronte and Adrano. Unlike the Mickey-Mouse-eared, pom-pom jollity of the ubiquitous fichi d'India (prickly pear) with which it shares this blackened lava landscape, the pistachio tree is no beauty. Indeed, it's the kind of vegetation you'd expect to find on a Star Trek stage set, its bare branches twisting and coiling from a short stunted trunk, a tangle of thin, rubbery octopus tentacles that look as though they could snake out and wind themselves around you if you strayed too close. But the fruit this tree produces every two years makes up for any shortfall in the looks' department. As the patrons of Sport-Bar Saitta are at pains to point out.

Of the seven thousand familes registered in the comune di Bronte, explains Antonio Petronaci of the local pro loco traders' association, more than half have a working interest in the ten thousand acres that comprise the pistachio growing fields. Some families have a handful of acres, others just a cramped, terraced smallholding with a dozen or so trees. But all of them share an equal passion for the pistachio. Up here in Bronte, it's not just a nut, it's a way of life. For weeks now families have been out on the slopes hand-picking the fruit from the trees, peeling off the soft outer skin called mallo, filling sacks with the just-split shells and heaving them home. For days the lava-block pavements of Bronte have been carpeted with plastic sheeting, each family's harvest raked out to dry under a gentle September sun, and in the warehouses of Nuncio Longhitano, whose family has lived in Bronte for generations, the shelling machines, the pickers and sorters, the baggers and weighers have been working overtime. As well as preparing Bronte's pistachios for export, Longhitano and his son Vincenzo have also been selecting the finest nuts for the family firm's celebrated Torrone, a nougat-like bar of chewy sweetness liberally studded with Bronte's celebrated oro verde – its green gold.

In 1799 it was this same green gold that provided a healthy pension of £3,000 a year for an unlikely beneficiary, the British admiral, Lord Nelson. Having rescued Ferdinand IV and his family from war-torn Naples, Nelson was rewarded by a grateful Bourbon king with the dukedom of Bronte – and most of the Simeto Valley which the town overlooks. Although the admiral never visited his estate (title and pension were probably good enough for him), roadsigns around Bronte all point proudly in the direction of neighbouring Maniace and Il Castello di Nelson. More fortified farmhouse than actual castle, it remained the family home for nearly two hundred years before the burghers of Bronte bought it back again from Nelson's descendants – doubtless plundering their lucrative income from pistachio production to pay for the purchase.

Lucrative it may be, but in terms of world markets Bronte's pistachio production is no front runner. With an average yield every two years of 35,000 to 40,000 quintales (1 quintale = 100kgs), Bronte's four thousand tons account for just three per cent of the world's supply. But while they may trail far behind Greece, Turkey, Iran and California in terms of production, the people of Bronte have not the slightest doubt that their pistachios are the finest, the tastiest and the most sought-after. Look at the colour, they'll tell you, pointing at the purple skin splitting open to reveal the green nut. Green, green, they'll say, not the weak, anaemic yellow you get everywhere else. And in Bronte's ristorantes, pasticcerias and gelaterias, the proof is there for all to see – steaming plates of pennette al pistacchi, bowls of nut-studded biscotti, tubs of freshly-churned gelati and trays of sugar-dusted fiori di pistacchi cakes, all of them as green as an Irish emerald.

Back in the Sport-Bar Saitta, the mood is getting lively. Espressos are giving way to shots of grappa and the hum of talk has risen above the scream of the motorinis. Outside in Piazza Spedalieri the town band is assembling for a final practice and as we crowd the door to hear it strike up, Signor Petronaci shoulders his way through to me with a frosted metal bowl filled with pistachio ice cream. Made that very afternoon, its domed head is powdered capuccino-style with finely-ground pistachio.

A single, icy spoonful is all you need to know about the Bronte pistachio. Pure, green heaven.