Starting a fire from cold and smoke coming out of splits

[myth83]

Good day everybody,

As a newbie, I pay extra close attention to small details that might make some wood heating experts sigh.. but I guess that this is how we learn

I have noticed last evening, starting a fire from cold, that as the kindling ignited good and started to warm up the firebox - the lower splits (which are always my bigger splits) in a top-down fire setup started to smoke despite that the fire hasn’t reached them yet and that my wood is fairly dry (an average of 11-14% moisture content by testing with a common moisture meter).

What is this smoke? What does it mean?
Why does it smoke like that?

On another note, could it be cause of the bark? I have always wondered if it is better to strip the bark or leave it as is.

I have attached a photo of that, to make it easier to understand what I am referring to.

Any information or tips are as always highly appreciated.

Thank you

 

[CincyBurner]

My guess: smoke from actively burning wood swirled around cool firebox and is temporarily trapped beneath the splits above it.

Usually better starts from cold if you use kindling/ splits that have rough (fine) edges that catch fire sooner, as opposed to smooth bark (branch wood).
Experiment with your stove. You'll figure out what works best for your setup: stove, draft, and wood.

 

[firefighterjake]

Your wood is about to ignite as it is getting heated up and about to reach the ignition temp.

 

[brenndatomu]

As the firebox temp comes up to normal operating temp and secondary combustion starts, watch that smoke trail burst into flames as it nears the top...fun to watch...

 

[Alpine1]

Wood burning can be roughly divided in three phases (which are not definitely separated):
1: water evaporation
2: off gassing (it’s the phase you were observing)
3: coaling
During phase 2, if the temperature is high enough, the gas released ignites and you see actual flames. Once all the gas has been burned, you have coals (essentially carbon, with little mineral content). Once all the carbon is gone, all is left are the minerals that we call ashes.

 

[Corey]

Wood burning can be roughly divided in three phases (which are not definitely separated):
1: water evaporation
2: off gassing (it’s the phase you were observing) ...

Yes, I would say mostly that ^. The radiant heat from the fire above is starting to bake some of the lightest / most easily vaporized water and hydrocarbons out of the log below. You see this vapor as smoke.

With a top down fire, 'in theory' that smoke from the wood below should get caught and pulled into the updraft of the fire above. It would then essentially burn up in the fire. Not always perfect, as sometimes other drafts/air currents in the firebox can cause the smoke to waft around the fire instead of into it. But if you minimize the 'excess air' and try to let the combustion air into the firebox in a controlled / non turbulent way, it helps.

You could take the bark off, but then it would just be the wood below which starts to smoke first.

 

[myth83]

Thank you all for your wisdom and tips! I appreciate it.