Re-Burning Wood Coals?

[GreenMountainBoy]

I've come across a question I don't have a definitive answer for. When I clean the ash out of my wood stove, I'm often left with un-burnt coal pieces ranging in size from a dime to a quarter around. My thought was to screen the ash in order to capture those coals and burn what's left of them in my next fire. I figured this would cut down on my wood consumption as well as my waste and cost.

However, when I mentioned this idea to my son, he claimed that re-burning the old coals adds more creosote to the system, making it less efficient and costing more in the long run. This seems like a reasonable argument, but I can't say one way or another - not enough experience with re-burning coals to form a solid opinion.

So, does anyone here have experience doing this that would care to share their opinion?. Is it worth screening those coals out of the ashes or no?

 

[bigealta]

Those are charcoal. just like wood chunk charcoal from the store. They burn great!

 

[stoveliker]

If the coals have been kept dry, then they are not a significant source of creosote - if burnt in a fire in a mode that does not produce significant creosote - i.e. burn right and it won't be a problem.

Not sure what the argument would be that they are creo producers; they are not. And having them "cold" in between fires is not going to change that.

 

[peakbagger]

Years ago in Boy Scout training, we would dip unused charcoal briquettes in a pot of water at the end of meal and then set them aside. Next meal we would light them again. The heat inside them would dry off any surface moisture.

Coals are mostly carbon, no creosote.

 

[Bad LP]

Personally I would just dump them. That’s a lot of effort for no gain.

 

[Mutineer]

Actually, the title of this posting shouldn't be "Re-burning.." because those coals have never been burned.
I have a slotted shovel with diamond shaped holes that I bought from Amazon or some over site a few years back that I use to sift the coals out of the mix. The only thing I discard are fine ash and sometimes clinkers that develop after a few days of hot burning of mainly red oak, those are clumped up mineral deposits, but the unburned coals are good to go. Waste not, want not, especially this year since I only recently shut down the stove and burned maybe 20% more wood than usual.

 

[cadyfatcat]

My stove insert has a grate which allows me to sift ash through the bottom and leave a clean pile of charcoal in the burn chamber. The more coal I leave there underneath my kindling the quicker the fire will start next time. If you watch underneath the kindling the coals will get red hot again when you start your next fire and provide a much hotter/sustained base for the fire. So if it's easy for you to separate them from the ash, I would definitely leave them in your firebox.

As far as creosote, those coals are dry as a bone, charcoal...going to be no creosote coming from them, and again the heat they provide to the initial fire next time around should help obtain more complete combustion on startup, thus reducing any creosote which might otherwise be produced in the lower temperature environment when you're starting with kindling.

 

[velvetfoot]

I try to wait for a warm day and let the coals burn down in the stove before emptying the ashes.

 

[Bobbob]

I always rake the coals back before cleaning out ashes. Then pull them forward and burn on top. They heat up quickly and get things roaring faster

 

[RockyMtnGriz]

Cleaning all of the ashes out of your stove is usually counterproductive. Some ash, especially if it's carbon-rich "black" ash, really helps in getting a fire started, and some ash of any description gives coals a place to nestle into away from the air helping to prolong the time that you can go without a cold start. I'll move the darker ash and any little coals out of the way, shovel out the white ash, then spread the dark ash and coals around to go again. I'll even dump my ash drawer contents onto a pile of coals if I'm trying to go 24 hours from burndown to the next reload. It keeps the stove just warm, keeps the draft healthy, and is easier than kindling a new fire. The warmer it gets, the more ash I try to leave in the stove for restart reasons. If it's really cold, and the firebricks are barely losing their glow between reloads, then it makes sense to get most of the ash out to make room for larger loads.

Maybe I'm nuts, but I treasure those charcoal chunks. If I know I won't be burning my cat stove for a few days or more, I'll make the last load a bunch of smaller pieces, then gradually turn it down to off. The volatiles get cooked out of the wood, and heat my house, while the rest remains to produce about a 5 gallon bucket of charcoal for me to grill with. By the time winter is over, I have a few dog food bags of charcoal in the shed for the summer. Seems to make more sense than buying it and hauling it from the city, and it saves more space for supplies I can't produce on-site when I make a town run. Plus, if there are pieces that don't get completely carbonized, they're like smoke chips - great for adding some smoke flavor that Kingsford just can't.

 

[firefighterjake]

I'm with BadLP . .. seems like a lot of work with not a lot of payback. Then again with the way I burn and my fuel I tend to mostly end up with fine ash at the end of a burn and not a lot of coals.

 

[Bad LP]

I'm with BadLP . .. seems like a lot of work with not a lot of payback. Then again with the way I burn and my fuel I tend to mostly end up with fine ash at the end of a burn and not a lot of coals.

Same. Very little coal chunks in both the insert and a few pieces in the front corners of the boiler. I prefer to burn hot, not smoldering fires. I also restart my fire in the insert buy stirring up the bed and dropping a load on top then let her rip.

 

[stoveliker]

Burning hot or not may not have anything to do with coals. Oak coals also when you burn full blast. So it may more be the fuel type.

It is my experience that a box full of oak won't leave black coals after cooldown; there is a long coaling stage but they do turn into ash. However if I burn oak mixed with maple (or another ash forming species), the oak coals can get buried and eventually extinguish if the stove is let go cold. Then I have some coals.

 

[Bad LP]

Burning hot or not may not have anything to do with coals. Oak coals also when you burn full blast. So it may more be the fuel type.

It is my experience that a box full of oak won't leave black coals after cooldown; there is a long coaling stage but they do turn into ash. However if I burn oak mixed with maple (or another ash forming species), the oak coals can get buried and eventually extinguish if the stove is let go cold. Then I have some coals.

I only wish I could burn oak. Any oak!! Maple, cherry, ash and birch is all we have here for harder woods.

 

[stoveliker]

yeah, warmer winters here but oak and locust to use (no hedge in my stacks though)... life's not fair.

 

[peakbagger]

I only wish I could burn oak. Any oak!! Maple, cherry, ash and birch is all we have here for harder woods.

Too late for us folks but Red Oaks are definitely moving north. I know of several folks who have been hauling acorns home and planting them north of Route 2 and having success.

 

[GreenMountainBoy]

Burning hot or not may not have anything to do with coals. Oak coals also when you burn full blast. So it may more be the fuel type.

It is my experience that a box full of oak won't leave black coals after cooldown; there is a long coaling stage but they do turn into ash. However if I burn oak mixed with maple (or another ash forming species), the oak coals can get buried and eventually extinguish if the stove is let go cold. Then I have some coals.

Thanks to everyone for replying, and I'm glad to find that there's a majority consensus that burning the coals is good.

I guess I should have mentioned, since it seems relevant in hindsight, that I'm presently burning the following mix: 80% red oak, 5% white oak, 15% hickory. So I guess the red oak is the source of a lot of that charcoal.

 

[Bad LP]

Too late for us folks but Red Oaks are definitely moving north. I know of several folks who have been hauling acorns home and planting them north of Route 2 and having success.

I left massive oaks in MA and always thought I'd bring up some nuts for fun. I quickly determined that I would be nuts and just buy a few seedlings.

 

[Cluttermagnet]

This has been an interesting thread. Personally, I value that charcoal and
I do use it as I start a new fire because I think it helps build the initial coal
bed much faster. I've never thought of it as a Kingsford replacement, but
that actually makes a lot of sense. I do save some, plus there is almost
always some charcoal when I open my cold stove. This may have a lot to do
with the fact I am running an older, pre-EPA stove, I dunno. Anyway, I am
burning clean with well-seasoned woods, a mix that includes maybe half
Red Oak during sessions. I agree, it's probably the Oak that leaves the
coals, Cherry not so much...

 

[Draughts15]

I rake them to the front and use them to create a little air space for my splits and kindling on a cold start. They get hot quick and burn down nice!

 

[patrickk222]

well my thoughts on reburning old coals is that as long as your not storing them out in the weather and ya add whatever u use for kindling they shouldnt really be adding creosote to your pipes and flue

 

[redyute]

I use them in the grill

 

[fbelec]

it's funny this thread came up. i use the same wood in my defiant as in my hearthstone2. the h2 produces more coals than the defiant. it might be the way that the air is introduced into the fire. so the h2 air comes into the firebox from under the fire thru the grate and leaves coals everywhere. so i let the ash go down thru the grate into the ash pan and then pile the coals in one spot open the ash door and propane torch the coals for about 30 seconds and close the door. after a minute or two i notice the firebox is bright, kindling and splits and i got a fire in minutes

 

[peakbagger]

On the original VC Defiant the primary air got introduced at the base of the fire along the back of the stove, at the loading door and a short length of the front of the stove. The front of the stove bulged out in the front and there was no air introduced. It was pretty standard that there would not be many coals along the air ports but the front of the stove behind the doors would be loaded with them. pretty much standard was when it was time to relight the stove in the am was to pull the coals from the mound behind the doors to the loading door. It would hold hot coals for days out front.

 

[Qvist]

I keep the large Coals, but throw many in the ash pile that are small.