What is Charcoal?

Over many weeks, I made many calls, inquiring about the energy that's burned away (wasted!) in the baking process and what benefits you get in return. Charcoal-briquet manufacturers in the United States couldn't furnish experts. The Department of Energy suggested I talk with someone in "fossil fuels."

"Charcoal is not a fossil fuel," I sighed.

"Oh, that's a fossil fuel," said the spokesman at the Environmental Protection Agency. "Charcoal is just old dinosaurs."

"Charcoal," I mumbled, "is made from trees."

Eventually, I stumbled across the Combustion Institute.

"What do you do at Brown?" I asked Dr. Hurt.

"I'm a professor of charcoal," he snorted, cracking himself up. Actually, he works a fair amount with "activated charcoal," which is made from charcoal. He doesn't actually study the charcoal-making process, but he's an accomplished-enough combustor that he could describe the process and imagine its benefits.

To make charcoal in a developing nation, you bake wood at a moderate temperature while it's buried under soil to deprive it of oxygen. (To make it in Missouri, where most of the domestic version is made, you use a more permanent oven.) This drives off the undesirable elements but keeps the carbon in the wood from burning.

The undesirable elements are: Lots of water, which cools fire. It might take a year of outdoor drying to dry the wood naturally. Volatile compounds, like methane and hydrogen, also are sent packing. And tars, which is a generic name for big, smoky, sticky molecules that form liquids when they're cool, are sent away in reeking, yellow clouds. The tars, in particular, can contain carcinogenic compounds, like benzo-A-pyrene, and, according to Hurt's calculations, "a zillion" other bad actors.

(This cooking process is messy. Missouri has historically exempted charcoal makers from some clean-air regulations, making it cheap to do business there. But laws in the making will require charcoal makers to clean up their act.)