# Burning charcoal in a wood stove?



## 48rob (Nov 27, 2010)

I read warnings saying it is very dangerous to burn charcoal in a wood stove, that it produces huge amounts of carbon monoxide.

I have no wish to die, ever, so I'm not about to do this, but I am curious...

When I clean out the ash from my stove, there are always chunks of vaying size of...char-coal.
As I understand it, commercial charcoal is the same thing, just more refined.
Ground up and mixed into a slurry, then drained and compressed into the familar shape we use in our barbeque grill.

Is it dangerous because of the refinement?
Is the danger of burning the (natural) charred wood in our stoves offset by the volume of wood that we burn along with it?

Rob


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## Backwoods Savage (Nov 27, 2010)

Rob, I guess I've never heard that nor considered doing it so no help there. 

I also hope you are not cleaning out all the ashes when you do the cleaning. The stove needs a bed of ashes to work well. We leave about 2" deep in our stove.


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## 48rob (Nov 27, 2010)

Hi Dennis,

 No, I'm leaving a couple inches of ash in the stove, but thanks for the tip!

I have a handy dandy sifter that I'm using (inside the stove) to separate the ash from the charcoal as I'm mixing some ash with a load of horse manure, sand, and soil for next years raised garden beds... ;-) 

As I was sifting, the thought came to me that it would be pretty dumb to not gather some of the nicer chunks of charcoal for use in the barbeque grill next year.
Guaranteed not to have any chemical binders or unknowns to foul my food.
, and a lot cheaper!

Rob


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## begreen (Nov 27, 2010)

This was asked a little while back. Pure charcoal is used around the world as a fuel, often indoors. It was the traditional fuel for the original Japanese hibachi. ( A room heater, not the cooking grille seen in the US.) http://en.wikipedia.org/wiki/Hibachi. That doesn't mean it's great for your health. Most of these homes had little choice and were not tightly sealed. 

Commercial charcoal briquettes have coal dust added and they do emit more fumes as they burn. Still, there should be 0% fumes from a properly running modern stove, so I am not sure the CO concern is always correct. However, in a leaky franklin with bad draft, this definitely could be dangerous. I wouldn't recommend burning them mostly because the stove is not constructed for this type fuel and it's an expensive way to heat. For alternative solid fuels, BioBricks, or super-compressed wood logs would be a better choice, but only when burned safely per label instructions. Compressed fuel puts out a lot more heat and can risk overfiring a stove when used improperly.


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## 48rob (Nov 27, 2010)

Coal dust huh?
Boy, learn something new everyday...

 I've no desire or intention to burn charcoal briquets in my stove, but sure was curious about why it was riskier than burning the charcoal produced by burning wood in a stove.

Thank you for providing such a detailed response!

Rob


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## spirilis (Nov 27, 2010)

48rob said:
			
		

> Coal dust huh?
> Boy, learn something new everyday...
> 
> I've no desire or intention to burn charcoal briquets in my stove, but sure was curious about why it was riskier than burning the charcoal produced by burning wood in a stove.
> ...


Yeah FWIW, I experiment from time to time with adding a couple charcoal briquettes in with my firestarter.  Seems to help but I don't have any solid measurements to prove.
The other problem is, burning pure charcoal in your stove might not work so well for the same reason burning Anthracite doesn't work so well in a woodstove (that's designed and tuned for burning wood)--it needs under-fire air to burn properly.  Although charcoal is much less dense than anthracite so I don't know if that's still accurate.

I had a silly thought of doing this with my downstairs stove (a supposed "wood/coal" convertible stove) with charcoal briquettes and I went all over the place jotting down prices for the bags vs. the weight.  Never came close to being worth it (compared to the WoodBrickFuel I buy, which is already a bit pricey) although I will say the Sam's Club el-cheapo charcoal briquettes (the ones that say "now 60% larger!") are the cheapest of all in terms of $$/BTU.  I bought a 2x15lb pack of them and use them for my experiments.


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## Corey (Nov 27, 2010)

The charcoal in your stove and the charcoal you buy are not significantly different enough to matter.  Especially if you buy bags of real hardwood charcoal - in which case they should be almost identical.

I think the main issue comes from the fact when you are burning 'natural' charcoal in the wood stove, you've had a big fire, established a good draft and proper flow through the wood stove.  It is all working as intended and venting the flue gas outside.  If you were to start with bag charcoal, you may not have a warm flue and good draft when the huge pile of charcoal lights off...it's pretty easy to have flue gasses flowing back into the house.


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## mliiiwit (Jan 15, 2013)

48rob said:


> I read warnings saying it is very dangerous to burn charcoal in a wood stove, that it produces huge amounts of carbon monoxide.
> 
> I have no wish to die, ever, so I'm not about to do this, but I am curious...
> 
> ...


The ash you remove from your stove is the byproduct of burning charred wood (charcoal).  When the wood has stopped actively flaming and is just glowing chunks, that is charcoal burning.  So no, it is not dangerous to burn in your stove assuming you have a positive draft to prevent any gas spillage into your living space.

I was also shoveling a lot of charcoal out with the ashes until I figured out this:  After your fire has burned down to just glowing coals, don't add more wood if you have a heavy bed of ash & dead coals.  Instead, churn the ash/coal bed to mix the live and dead coals.  Repeat as needed to maintain a glowing bed of hot coals, for up to several more hours of good heat output.  I do this in the evenings when I'm home and can tend the stove regularly.  This will consume a lot more of the unburnt charcoal and significantly reduce the volume of material you are shoveling out of the stove.  My experience doing this indicates there is a LOT of heat to be recovered by burning the unburnt coals in this manner.  Plus, I'm shoveling ashes less often.

However, I'd still recommend sifting the charcoal out of your ashes.  You can either throw the coals back into your stove for the heat, use them in your grill with your grilling charcoal, or you can use them as garden soil amendment.  There are other uses for the charcoal too.


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## WillyMaykit (Jan 30, 2014)

The claim that Charcoal is too hot for a woodstove....
It has never deformed or otherwise hurt my Weber-grill, which is made from far thinner steel.
So, I have to call BS on such a claim. (Probably based on good intentions)


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## Jags (Jan 30, 2014)

Considering this is a thread from 2010, I think we will just shut this one down.


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