Monday, 20 November 2017

Why Charcoal Doesn’t Smoke? Firewood burning explained

Anyone who ever sat by the campfire asked the same exact thing. Why does the burning wood make that crackling sound and why charcoal doesn’t smoke? Not that anyone’s complaining. After all, the majority of people would claim that there is nothing more practical for campfire, but still, it makes one wonder. After all, humans are curious creatures. Because of all this, here are some insights into what happens when the firewood is burning, as well as an answer to the question of why charcoal doesn’t smoke.

firewood burning explained

What is Fire?

Even though this question might seem as too absurd to ask, we must return to it one more time. Fire is a chemical reaction between oxygen in the atmosphere and a source of fuel. Sources of fuel can be numerous, including gasoline, coal or wood. In this particular case, we are most interested in the last one. Now, you’re probably wondering if all it takes are air and wood, why all trees aren’t burning all the time. Well, it’s a bit more complicated than that. In order for fuel to burn, it must reach the temperature of its ignition. For wood, this temperature is roughly 180 degrees Celsius or 356 degrees Fahrenheit. What this means is that a long-leaf wood (which has the fastest ignition by far) would need around 14 to 15 minutes to ignite on this temperature.

What Happens Next?

When the combustion reaction has occurred, the heat decomposes cellulose in the wood. This happens in three major stages. The first thing that happens is that volatile gases exit the wood as smoke. Next, the wood turns into charcoal or pure carbon and gets formed. Lastly, the minerals that cannot be burned remain in the form of the ash.

So, Why Does Charcoal Not Smoke?

As we already mentioned, charcoal is what remains of wood when all the volatile gasses are heated up to the point where their molecules break apart and start recombining with oxygen. This happens when these gasses reach the temperature of around 500 degrees Fahrenheit. So, the charcoal doesn’t smoke because it is basically just the wood from which all those gasses that make wood are removed.

Not 100% Smoke-Free

One last thing, even charcoal is not 100% smoke-free. When we say it doesn’t smoke, what we mean is that there is no thick black pillar of smoke coming out of it. On the other hand, the heat from the fire may cause fluids within the wood to boil, which will cause a bit of white steam to leave the fireplace. Even though this steam cannot be seen most of the time, it can often be heard. Namely, as it forms, it causes pressure on the wood around it. Once this wood starts to break, we hear a crackling noise. There you have it, yet another mystery explained.


It is in our nature to get fascinated by the things we cannot understand. Still, this doesn’t mean that the truth is any less exciting. Sure, it doesn’t take the expert in molecular physics to set up a barbecue or make a campfire, but it also doesn’t hurt to know a thing or two about how this all works.

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