Creosote formation

[Woodsman on the Plains]

My buddy and I are having a little discussion about when creosote does and does not form in your chimney. I was always under the impression that creosote forms while wood is burning during the combustion process but more so at the beginning, towards the end of the fire when it's burned down to coals and hardly any flame the creosote is pretty much nonexistent. Therefore if you're flue temps are low (200's) there's no need to worry about creosote at that point. He on the other hand is saying that creosote forms at any point during the fire, even at the end. What is everyone's thought or is there already a thread with this same discussion somewhere?

 

[30WCF]

Early and late
Any time there isn’t enough heat/draft to get moisture out the chimney before it condenses, which is highly dependent on wood m/c and conditions (pipe, double/single wall/classA/attic chimney/exterior wall chimney…

 

[Woodsman on the Plains]

What about at this stage? A nice hot bed of coals. I would assume no creosote should be forming at this point.

 

[30WCF]

Clean your glass off and shut the door and see if you get more blackening at that point or when it’s ripping at 700 degrees.

 

[bholler]

What about at this stage? A nice hot bed of coals. I would assume no creosote should be forming at this point.
View attachment 319828

Creosote will not form during the coaling phase like that you are correct

 

[bholler]

Clean your glass off and shut the door and see if you get more blackening at that point or when it’s ripping at 700 degrees.

You won't get blackening from coals. It just doesn't happen

 

[BillBurns]

Im under the impression that it forms the most towards the top of the stack. As it cools, it forms. In my mind, anytime wood is burning, its making creosote. I am probably wrong, but thats how I look at it.