ROMOOS, Switzerland (Reuters) - In the remote hills and valleys of central Switzerland, mountain farmers are still making charcoal to a centuries-old method.
Charcoal, formed by removing water and tar from wood, burns with almost the same intensity as coal, and was once the main fuel for medieval glassmakers and blacksmiths, and a source of energy for Switzerland as it industrialized in the 19th century, until imported coal became available.
Its controlled production can be traced back globally at least 3,500 years. Now mostly used by the world’s poor, charcoal in Switzerland serves mainly to grill food, for instance in barbecues.
Charcoal-burning, once a major cause of deforestation in Europe, largely disappeared from Switzerland in the 20th century, but experienced a temporary revival during World War Two when neutral Switzerland was unable to import coal.
It was never interrupted in the Napf region, some 30 km (20 miles) east of the lakeside resort of Lucerne, where it dates back to the middle ages, when glassmakers practiced their craft in the 13th and 14th centuries.
But the back-breaking lonely work is far from being a quaint tradition revived for tourists. Also practiced in some remote parts of former East Germany like the Harz mountains, it is for smallholding farmers a vital source of income.
The little village of Romoos, whose name goes back to an ancient Germanic word for tree-trunk, is at the heart of the area of steep hills and valleys, where tractors crawl along the slopes as the farmers and their wives mow and rake rich mountain grass for winter hay.
In hollows in the woods, farmers build charcoal kilns, the shape and size of small igloos.
Willy Renggli, head of the charcoal burners’ association, shows how a kiln is built up.
On a spider-web base of tree trunks, one-meter long logs are stacked up in two layers around a central shaft or flue.
The best wood for charcoal is beech, but pine and other timber will do.
The kiln is topped off with smaller pieces of timber, then covered with branches of fir needles, and finally coated with a thick paste of charcoal grindings, ash and water.
A typical kiln uses about 60 “Ster” of timber, Renggli says. A “Ster” is a Swiss measurement corresponding to one cubic meter (10 cubic feet) of wood, weighing about 600-700 kilos.
Each “Ster” of timber yields about 100 kilos of charcoal.
It takes two men about three weeks to build the kiln, which will then burn for 12-18 days.
The charcoal-burner will spend the entire time by the kiln, camping out under canvas while it burns, says Renggli, 51.
Every few hours he feeds the kiln with charcoal chips, letting in air by piercing the charcoal paste covering and regulating the heat by sealing it again.
Around 50 barrels of chips will be used up in a single kiln.
“I can sleep 2-3 hours at a time. But I sleep as well as I do when I‘m in my white bed up there,” he said pointing up the hill towards his flower-bedecked traditional farmhouse.
Once the kiln is burning it can generate a heat inside of up to 800 degrees Celsius (1,472 degrees Fahrenheit).
But the charcoal-burner can walk barefoot on the kiln if the charcoal paste has been applied properly.
“I need about 500 degrees to get the charcoal process going,” Renggli said.
If the charcoal-burner neglects tending the kiln every few hours, or misjudges feeding or aerating it, the fire may go out -- or the charcoal itself will catch fire, burning out with an intolerable heat.
As a result, the work is best done by a single burner who can monitor his kiln precisely.
“The charcoal burner who lights the kiln must burn it through to the end,” Renggli said.
The Swiss authorities have tried to get unemployed people to work as burners in shifts, but they only produced one third of the charcoal a professional would have done, he recalled.
The work, though tough, is a useful sideline, even if it brings in only about a quarter of the earnings he gets from his farm -- a 10 hectare smallholding producing milk from nine cows and seven goats.
In addition, to make ends meet, Renggli and his wife have joined the agrotourism trend, taking in guests who want to experience life on a farm, and he helps out as the local postman.
The craft of charcoal-burning is usually passed down generations although Renggli, one of a dozen active burners in Romoos, says he learnt it from his neighbors.
But his son has already built and fired some small kilns with 5 or 6 “Ster” of timber.
Editing by Sara Ledwith