Cold Weather and Coaling Question

WHY?????

I've been thinking about this and I cannot come up with a satisfactory/scientific reason as to WHY our wood coals so much when is gets really, really cold out.

Anyone???

 

I don’t think it does. The stove puts out less heat in the coal stage. When less cold that is still enough and we let the coals burn down. When really cold, we burn faster/hotter and reload sooner, before the coals have been consumed.

 

You're just adding wood earlier. That's all.

Really cold temperatures increase draft so technically it burns coals faster all other variables being equal.

 

Isn’t this the caveat of being Easterner?
More hardwoods than soft by far, I’m fortunate to have both but let’s be realistic that your hardwoods where you are much more tight grained so burning down coals is a harsher process in the cold there than it is here. I noticed that my black locust burns well but sometimes not as long as east coast Oak. However I have been burning less of that wood because of how ridiculously hot it gets my house.

I hear a lot about how softwoods are so often used in this western but not necessarily warmer areas that hardwood would be great to have but the folks that burn, still get by with what they got. My advice to you is to hope you can find a pine tree or two for the burn. I know I get coals a lot when I loaded up birch. Yes white birch. Some folks think this stuff has been dammed for being such a soft wood for a hardwood but hardly the case here. In fact, it’s highly coveted as a firewood that people pay a premium for it...the coals just seem to work better during the 20-40’s here...

 

It's Coaling more because you're burning faster. However, with the added draft, my coals burn down much faster. What used to take about two hours now takes an hour.

 

That's a very good question I have been trying to answer.
We are not talking about burning coals down here, we are talking about very cold weather coals being created phenomenon.
This phenomenon may be very different if you have a hybrid or cat stove.
I can burn the same wood from the same tree if it's cold, it ends up coaling more when is very cold.

 

I don’t see any difference in coal creation with colder weather. Not with my older non-cat or my new hybrid of my smoker for that matter. As you burn off the volitals, wood turns to coals.

 

If I understand you correctly then a lot of coals means the cat system is functioning properly?

 

No, I don’t think the cat plays too much of a role. If you heat wood without enough oxygen to burn, the water will boil out and so will all sorts of other chemicals if you get hot enough. The end result is charcoal.

If we do it in an EPA stove, the gasses released get burned buy the secondaries and/or the cat and also by the primaries if there is enough air let in. In a non-epa stove, fire place, stick burning smoker, camp fire etc. there is only the primary flame but it is still doing the same thing. The first things consumed in the flame stage are largely the chemicals that gas off and the remainder is coals.

How fast the coals burn and therefore how much is left after the other compounds burn away is a function of airflow. If most of the air let into an EPA stove is secondary and cat air, you will have more coals left. If most of the air fed to a fire comes from below, the coals will burn faster and hotter and won’t build as much.

The role that the cat does play is it allows you to heat the wood without directly burning it with primary air. You can basically make charcoal running in pure cat mode. This is more efficient than old stoves, but at some point we need to add primary airflow to the coals to burn them down. Often we can open the vent a bit, let more air in and the coals keep the hose warm. When it is super cold like this past week, that may not put out enough heat on a modern stove so you are tempted to reload sooner before the coals burn down. Other than that, I don’t believe outside temps play much of a role in the process.

 

On a similar note, how many of you notice the increased draft created by cold outside temps and/or increased winds kinda make a ‘cruise control’ situation?

I’m into my third winter without my BKK, which got sold with the house, but I can remember getting up in the middle of the night when the wind started howling and the bottom busted off the thermometer, only to find the BK blazing away at much higher temps than when I went to bed. I always assumed from increased draft at the same thermostat setting. Convenient.

And I burned a few loads in the super 27 at our vacation home the last couple days with temps in the zeroish neighborhood. I normally run the air control all the way closed and then opened up a hair, and typically get stove top temps in the 450-500 range at the peak in more moderate outside temps, but Sunday night and Monday morning the same setting got me 650-700. And that was fine because the house was fricking cold when I got there. Also convenient.

Giant red oak splits in that blaze king gave me all kinds of problem coals in cold weather. I found myself loading much smaller splits of ash and the like to make the most heat with minimal coaling. But in contrast, big red oak splits would get me the highest temps in the 27. Currently burning sugar maple and beech, which I’m pretty happy with.

 

This theory makes sense to me. In our owb we are reloading more frequently to maintain water temperature. In warmer weather we are not as concerned with water temp dropping a bit so we allow existing coals in stove to burn down more between loadings.

 

I too have noticed more coaling when it is colder outside. My coals remind me of clinkers.
Once the house is up to temperature, I open the damp to full air and rack the coals. After an hour and several rackings the coals have burnt down to ashes. I then reload with wood. It seems to work for me.
I kind of believe my coaling problem is related to choking down the inlet to get more secondary burn. Wasn't doing that in past years.

 

Yep, that is it. Coals burn slower than wood and so put out less heat; if really pushing a woodstove, the output falls off enough when the wood is gone that we load more wood but all the coals from the first batch are still in there, burning down slowly. Then the second batch of wood, which was smaller in the first place 'cause of the previous coals being in the way, is burned down and makes even more coals. Eventually, the stove has so much coaling in it that it cannot be loaded with any more wood nor will it put out enough heat to heat the house.

All of this is only a problem in top drafting stoves, which is virtually all that is made these days. Bottom drafting stoves, such as the classic pot bellied stove, burn the coals down with the wood so just do not develop this situation.

One way to reduce or mostly eliminate the problem is to introduce more of the draft at the bottom of the stove or better yet, under the grate. Then the coals burn down AS the wood burns down and the problem is reduced.

Brian

 

It surely is a thing (increased draft) and I think we've had some fun discussions over the last couple years on the board relating to draft/chimney height/cold weather and wind.

 

A couple of really dry pine splits will crank out the heat while the coals burn down without perpetuating the problem.

 

My Fireview had a terrible coaling problem. But the Palladian and Progress never ever do. I'm not sure why.

 

Doesn’t need to be pine. Opening up the air intake will burn down the coals. If that doesn’t put out enough heat, adding one or two fresh splits will increase the heat output while the coals burn.

 

I've noticed I get more coals because my loads are fuller (more wood to create coals) and packed tighter (less air flow around the logs) in the colder weather. And also because of denser wood with tighter growth rings and larger splits (mostly red and white oak in my case) being used for the real cold weather. It all adds to the problem.

 

No, it doesn't need to be pine. But if I'm trying to burn coals down, it's nice to use some wood that won't leave more coals.

 

I open the ash tray door just a crack, and the coals burn right down in no time. And yes, colder temps = more wood = more coals

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