I'm walking through nature's mini-bar, though taking a cocktail in this heat would be suicide. My guide, or barman as I'm tempted to address him, stops again as we heave ourselves through the viscous floors of the ascending forest. He plucks a spindly white plant out of the ground.
Pressing it against my nose I'm taken away from the forests of the remote far west of El Salvador and transported to the veranda of one of the bars nestled miles away on the country's Pacific coastline. The aroma of lime is so accurate, so utterly there in its sweet acidity that it only needed a straw and a beaming barmaid in order for it to become the perfect caipirinha. "This is called the Arrayn Silvestre," says the guide. "But it is not the best smelling – there is plenty better in El Imposible."
He was right. As we walked through the forest, the sensation of browsing through a mixologist's fridge was only enhanced. There was the sapuyulo flower, which has the redolence of fizzy orange, the wonderfully named Aramon del Amanecer (meaning "smell of the sun rising") which gives off bananas and toffee. And then, just to prove that even the best cocktail mixer can have an off day, there's Izote, a weepy pale flower that smells of raw chicken meat. El Imposible may be the name of the park but, as I later discover, the effluvium of this area was the last thing visitors here used to concern themselves with.
El Salvador is a jumble of contradictions. The people are known as the "Japanese of the Americas" because of their work ethic, yet you can't walk around the capital, San Salvador, for more than a minute without seeing hammocks for sale. People are immaculately dressed but the litter problem in the cities is acute. Locals drive new US cars in neighbourhoods where people struggle to meet the $60 a month needed to pay for a government home. Surf fanatics come from across the globe to ride the tides on the La Libertad stretch of the nation's coastline, yet most tourists give the country a wide berth when visiting the region.
The seven million Salvadoreans are getting fed up with their nation's reputation. In the Eighties the civil war, along with a succession of earthquakes, brought the smallest country in the Americas to its knees. Even today, the bad-mouthing just won't go away. This is in no small part due to the Maras – gangs formed among the huge expatriate communities working in Los Angeles and other US cities. In 2001 the national currency, the colon, was scrapped to make way for the dollar. The contradictions continue. The country is a pioneer in solar power but deforestation is rampant and smog engulfs San Salvador on most days. I'm quickly being engulfed by confusion and endearment in equal measure by this country, exalted by PJ O'Rourke during a trip at the height of the Eighties civil war as having, "the scenery of Northern California, the climate of Southern California plus... no Californians."
No Californians, nor anyone else, appears to be in the vicinity of El Imposible national park. Hard against the Guatemala border, it is named after the treacherous path that farmers would follow in order to get their coffee crops from these cloud-diademed peaks down to the port town of Acajutla. This eight-hour trip by mule involved, at one point, traversing a ridge on a path only a few centimetres across, with a 2,500m drop to one side and a 3,000m drop to the other.
Nobody knows exactly how many died, but locals suggest that well over 100 never made it across. Many farmers would ride their mules to the imposible crossing and arrange for other mules to meet them at the other side. Those mules that did attempt the walk across did so blindfolded to stop them panicking. Forty years ago, a rudimentary bridge was constructed, and coffee growers still take their mules across it. A simple plaque at one end of it reads, Mayo 1968 – dejo de der imposible: "May 1968 – it is no longer impossible".
The trees change colour from lusty greens to pupil-slashingly bright yellows around here. The ground swells and bulges as we drive across the crisp, sharp teeth of the mountain ranges, which contain some of El Salvador's 25 volcanoes. My ears have popped so many times I fear that somebody may have stuffed a sheet of bubble wrap in there. The mountainside shows variants of hirsuteness. In places it is luxuriant with forest, growing on old coffee plantations. In others the soil is scraped back to reveal the earths' scalp. Here, sugar cane, coffee and cotton are grown by industrious local farmers. Many of them got their livelihoods back only recently after decades of land being carved up among the "14 families" ruling elite, which has dominated El Salvador's many misfortunes.
Vast areas of this part of the country were out of bounds until a peace agreement was signed between the military and the FMLN leftist guerilla rebels in 1992. There is little evidence of the war now save for the occasional old military check point. One we passed on the way from El Imposible to the town of Suchitoto in the centre of the country (prime FMLN rebel territory) was shelled within a day of opening back at the height of the conflict. The abandoned remains of the building take on the appearance of a slab of cheese infested by mice, such is the profusion of bullet holes.
The Spanish heritage of the country is nowhere more obviously on display than in the small town of Suchitoto. The original capital of the country was settled just down the road in 1524 by the conquistador Pedro de Alvarado. He picked a good spot: the view over the Lago de Suchitlá*from the adobe roofs and rolling countryside is glorious on a spring morning. Bicycles wheeze and clunk along the cobbled streets like a skiffle band on their last legs. Men with drooping sombreros the colour of wet batter, and with moustaches flecked with grey, sit on the chipped pavements in silence. Their faces are convulsed by secrets of the past. Two-tone aquamarine walls with shuttered windows and colonial-era wooden doors partially open to reveal a thumb-sucking child or brooding teenage girl.
I spent a sultry afternoon here, shying away from the heat in a overgrown courtyard near the town's main square, with a former FMLN guerilla. Jerry was responsible for communication between rebel troops in the remote forests around El Imposible in the early years of the Eighties. Along with six other former resistance fighters, he runs a hostel in the town called La Casona. The bar is covered in flags and posters of other Central American leftist movements.
We ate a simple meal. First, refried beans that had the texture and colour of clay but a lip-tingling taste. Next, pupusas: flattened tortillas the size of a beer mat, filled with cheese, pork rind and beans. The national obsession with the pupusa in El Salvador is such that the government has declared a National Pupusa Day, to be celebrated on the second Sunday in October.
To finish were huge platano: giant plantain with skin as smooth as worn vinyl, a body the colour of old linen and a taste redolent of long naps and butterscotch.
Jerry spent the final years of the war in the capital city. "I was most scared when we were holed up in a building in San Salvador for weeks on end in 1989", he tells me. "That was the time when the government started dropping bombs on us. I never thought that they would bomb our own capital city. We were totally trapped. Peace was essential – the whole country benefits from it now."
We embraced and said goodbye on the dusty street outside. The sun was sinking behind the lago on another day of post-war freedom for Jerry and his comrades. Protest music from Venezuela blared out of a passing car. "This is what I mean," exclaims Jerry cocking an ear at the pro-Chavez lyrics. "That would never have been allowed during the old days. We're free now. It's just such a shame that the outside world hasn't really noticed yet."
The writer flew from Heathrow to Chicago with Virgin Atlantic (08705 747 747; www.virgin-atlantic.com) and onwards with TACA (0845 838 7940; www.tacaairlines.co.uk) from Chicago to San Salvador.
The writer travelled with South American Experience (0845 277 3366; www.southamericanexperience.co.uk), which offers a similar one-week itinerary, taking in San Salvador and El Imposible, from £795 per person.
The Hostal El Imposible (00 503 2 411 5484), within El Imposible National Park has cabins sleeping two-six people. Rates start at $20 (£11) a night.
Bosque El Imposible National Park (www.salvanatura.org).
El Salvador Tourism: 00 503 2 243 7835; www.elsalvador.travel