I was looking at the photos Ben has on charcoal making in Lakehurst. I was always a little confused about just why charcoal burns better and hotter than the wood they make it from (not to mention the fact that it seems wierd to me to have a big wood fire, and then to be able to burn stuff again from the remnants). Anyway, I found this at discover.com that provides the best explanation to a non-scientist like me. I edited some stuff out:
What is Charcoal?
Traveling in developing nations, I've often wondered why people cook over charcoal. It seems so labor-intensive to stack up wood in huge, dirt ovens and bake it slowly down to little black lumps. Why not just burn the wood?
Eventually, I stumbled across the Combustion Institute.
The Combustion Institute keeps tabs on professional combusters, and they recommended I talk to one Dr. Robert Hurt at Brown University.
"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. 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.
Anyway, with the volatile component baked "away," you're left with a heap of black stuff that's just 20- to 25-percent of the original volume of the wood. It's chiefly carbon, with traces of volatile chemicals and ash. And when it burns, it won't belch smoke, and it will burn long, hot and steady. So, charcoal is just wood with the messy and dangerous parts baked off. (Charcoal briquets are a little more than that -- they often have additives: borax to bind the charcoal; nitrate to ignite it; and lime to whiten the ash so you know to begin cooking.)
You toast marshmallows over the coals of your campfire, not over the leaping, gassy flames of the wood. Once the gasses are gone, the oxygen in the air around the coals is able to come in and steadily pick off carbon atoms. These freshly-built molecules fly away as carbon dioxide or, in trace amounts, carbon monoxide. These scorching-hot gases, Hurt says, rise up and heat your marshmallow.
And activated charcoal? The stuff in aquarium filters and drinking-water filters and air filters? If you let oxygen eat at charcoal a bit before extinguishing the flame, it bores countless tiny holes into the surface. These holes are marvelous at trapping molecules of filth from the water or air passing through. Activated charcoal is just burned charcoal, overcooked by amateur combusters who ignored that white ash on their briquets.
Source: discover.com
What is Charcoal?
Traveling in developing nations, I've often wondered why people cook over charcoal. It seems so labor-intensive to stack up wood in huge, dirt ovens and bake it slowly down to little black lumps. Why not just burn the wood?
Eventually, I stumbled across the Combustion Institute.
The Combustion Institute keeps tabs on professional combusters, and they recommended I talk to one Dr. Robert Hurt at Brown University.
"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. 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.
Anyway, with the volatile component baked "away," you're left with a heap of black stuff that's just 20- to 25-percent of the original volume of the wood. It's chiefly carbon, with traces of volatile chemicals and ash. And when it burns, it won't belch smoke, and it will burn long, hot and steady. So, charcoal is just wood with the messy and dangerous parts baked off. (Charcoal briquets are a little more than that -- they often have additives: borax to bind the charcoal; nitrate to ignite it; and lime to whiten the ash so you know to begin cooking.)
You toast marshmallows over the coals of your campfire, not over the leaping, gassy flames of the wood. Once the gasses are gone, the oxygen in the air around the coals is able to come in and steadily pick off carbon atoms. These freshly-built molecules fly away as carbon dioxide or, in trace amounts, carbon monoxide. These scorching-hot gases, Hurt says, rise up and heat your marshmallow.
And activated charcoal? The stuff in aquarium filters and drinking-water filters and air filters? If you let oxygen eat at charcoal a bit before extinguishing the flame, it bores countless tiny holes into the surface. These holes are marvelous at trapping molecules of filth from the water or air passing through. Activated charcoal is just burned charcoal, overcooked by amateur combusters who ignored that white ash on their briquets.
Source: discover.com
