Britons have come to love barbecuing. The nation’s desire for a side-dish of fresh air is now so popular that collectively we burn upwards of 40,000 tonnes of charcoal each year. Such is the scale of our atavistic urge to eat outdoors that charcoal with a wholesale worth of £20 million goes up in smoke annually.

The downside for our rural economy is that the lion's share of the charcoal is imported. But while this sum only just dents the UK's balance of payments, the extraction of timber -the raw material for charcoal- is, in some instances, crippling remote and fragile wildlife habitats.

Huge volumes of charcoal wood are cut in already endangered tropical forests in south-east Asia and south America, while mangrove swamps can also come under pressure from timber extraction. In the past 20 years, about half of the earth's mangrove swamps have been destroyed. To make matters worse, their loss is also linked to coral reef destruction. To add to this tale of woe, there are new fears over the removal of cheap charcoal lumber from some west African forests.

Not all the imported charcoal we burn is the product of short-sighted exploitation. Far from it. But a great deal is. Regrettably, too many punters shambling up the high street are oblivious to the existence of bad practice. While for other, more aware, shoppers, the assortment of brands and packaging, coming in all shapes and sizes, makes it difficult to discover which charcoal is the best buy environmentally.

Very few, however, put conscience before the delights of a chargrilled chop. But some do, and their concern provides a welcome shot in the arm for British craftsmen who claim a solution lies close to home. And it's a solution that would at the same time revitalise the ancient woodland skill of charcoal burning in this country. The answer- cook with British charcoal.

Jim Bettle, who runs The Dorset Charcoal Company, is one of about 300 charcoal burners who is making sure that we have the opportunity to pick up a bag of local charcoal.

"Charcoal is a worthwhile way of increasing the return from otherwise low-value wood.
I've been charcoal burning since about 1996, working in conjunction with an independent forestry advisor," he says. Before that, he was involved in other rural trades, including thatching.

Operating with his five circular metal kilns, in about a 15-mile radius of his base near Wimborne, he will have at least three kilns on the go for up to nine months of the year. In winter, short days and a lower charcoal yield put a stop to business.

Traditionally, the stack was built only of wood, heaped with soil. Now Jim's kilns are of steel, fabricated to be transported on a trailer.

"There's no money in taking the wood to the kiln. I have to set up in the wood, convert it into charcoal in situ and then extract it."

Each kiln -akin to a big cylindrical drum with a removable lid -sits on eight separate rectangular feet, each about a foot long.
"The proper name for them is ports," says Jim.

Pipe chimneys fit alternately into four of the ports to allow the smoke to escape. While the four ports without a chimney funnel in the air, soil is used to bank up and seal the gap between the ports.

Stacking the kiln is the big job. First, wood is laid to channel the air from the ports in to the heart of the kiln.
"Then, I build a raft of wood on top. I work in a circular fashion, starting in the middle with the thickest wood and, as I work outwards, start to introduce the thinner stuff," says Jim.

All English charcoal burners use hardwood - not resinous soft woods -the principle being that a good firewood log will make good charcoal."

Historically, different charcoal woods had different functions. Alder was once the wood of choice for inclusion in gunpowder. During the Napoleonic Wars, the 855 tons of gunpowder made each year by The Royal Gunpowder Factory at Waltharn Abbey, Essex, held about 15 per cent charcoal, which required about 400 acres of alder- wood coppice to support production. An acreage considered by historian Oliver Rackharn as surprisingly little to fuel a world war.

Jim charcoals a lot of ash, oak, beech and sycamore. Some is from overstood coppice, some is thinnings and even tops go in.

"Once the kiln is full, I remove the chimney, leaving a hole down through the stack. I then tip a brazier -or bucket -of fire down the hole to ignite a pile of charcoal at the bottom. This gets the whole lot roaring."

The circular, slightly domed, metal lid goes on, but is propped up for about half an hour. When the fire has spread within the kiln, the lid is then lowered. Final sealing with soil is done and the four chimneys are put in place.

So what dark secrets lie within?

"It is important to realise the wood is not burning as such. The heat from the timber, sacrificed initially to get it going, is driving out moisture as well as oils in the wood. It is this wood gas, which ignites at the top of the kiln, that carbonises the stack. The heat travels downwards from underneath the lid."

How long the kiln is left to burn depends on the species and how seasoned it is.

“As a rule of thumb, it’s about 14 to 16 hours. Inside the temperature rises to more than 350ºC.

"The last few hours are critical. It's now especially important to monitor the colour of the smoke. While it's chuffing away white, you know you are still burning off gas. But when the smoke turns blue, you know charcoal is getting burned; the smell alters, too. Then it is time to shut down the kiln pretty quickly. Get it wrong and you’ll end up with a pile of ash.

"I’ll work round them, shutting off the air with soil, perhaps leaving a single chimney for 10 to 15 minutes to get all the smoke out. Once extinguished, it will cool in 24 hours. When you take the lid off, the wood looks exactly the same, except it is now 90 per cent carbon.”

Imported stuff, says Jim, has a maximum carbon content of only 60 per cent, thus the barbecue produces more flame, which singes rather cooks the meat. Likewise, the firelighters and lighter fuel you have to use to get it going because of its lower carbon level can taint food. British charcoal, with its higher carbon level, needs only paper as an accelerant for lighting. It also reaches cooking temperature faster.

"The charcoal is then seasoned in the air for a few hours -to make sure no re-ignition is possible -before bagging and grading by hand, says Jim. "If the rain gets at the charcoal at this stage, it has to be dried on sheets."

The smallest pieces are sieved to remove dust. The result is that of the one and half tons of wood that went into the kiln, a quarter of a ton of charcoal comes out.

Arguably, it is the oldest refined industrial fuel in the world, in use, perhaps, as long ago as 5,500BC for smelting copper. Today, the majority of The Dorset Charcoal Company's output is for the barbecue, though a fraction goes for art, horticulture, soap, filtration and even old-style building mortar. A 3kg bag for the barbecue costs about £4.

Jim is still building his business. But would he, too, seek to expand into overseas markets like his competition? "I'm not averse to the odd run to London, but I do believe in local to local. Though some charcoal has an environmental stamp, I wonder how it can be when it has travelled so far."

British charcoal- ideal with British meat in the great British summer. .

For further information, contact The Dorset Charcoal Company, tel (01258) 858064, or visit www.dorsetcharcoal.co.uk
Also worth trying is the BioRegional Development Group, which supplies UK-made charcoal to B&Q. For further information, tel (020) 8404 2300