Wood is too dry...
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Kilks
New Member
I am not certain about the validity of the arguments presented on this site, but I had remembered reading this before and dug it up again when I saw this thread.
It is information from http://www.chimneysweeponline.com/howetwd2.htm
Wood that has been seasoned for 9-12 months still contains about 20-25% moisture, most of which is wood resins. These resins play an important part in the three stages of wood combustion. During Stage 1, the kindling fire warms up the fresh load of wood and any remaining water content is removed by evaporation and vaporization. As the wood reaches 500 degrees or so (Stage 2), the resins begin to break down chemically, and volatile gases are released which squirt out through the wood fiber and ignite, boosting the temperature of the fire to around 1,100 degrees and producing 50-60% of the heat value from that load of wood. As the gases burn away, the flames finally attack the wood fiber itself (Stage 3), and extract the remaining heat value through the process known as charcoaling.
If your firewood has dried to the point where it has lost its resin content, your fire will go directly from Stage 1 (warming up to combustion temperature) to Stage 3 (charcoaling), skipping Stage 2 and missing out on 50-60% of the heat (and burn time) you'd expect to get from that load of wood. Here's what the US Dept. of Energy website has to say about too-dry fuelwood:
"Some well-seasoned wood can in fact be too dry for today's airtight stoves. If you place wood that is too dry on a bed of coals, it will instantly give up its gases as smoke, wasting unburned smoke and producing creosote buildup."
It is information from http://www.chimneysweeponline.com/howetwd2.htm
Wood that has been seasoned for 9-12 months still contains about 20-25% moisture, most of which is wood resins. These resins play an important part in the three stages of wood combustion. During Stage 1, the kindling fire warms up the fresh load of wood and any remaining water content is removed by evaporation and vaporization. As the wood reaches 500 degrees or so (Stage 2), the resins begin to break down chemically, and volatile gases are released which squirt out through the wood fiber and ignite, boosting the temperature of the fire to around 1,100 degrees and producing 50-60% of the heat value from that load of wood. As the gases burn away, the flames finally attack the wood fiber itself (Stage 3), and extract the remaining heat value through the process known as charcoaling.
If your firewood has dried to the point where it has lost its resin content, your fire will go directly from Stage 1 (warming up to combustion temperature) to Stage 3 (charcoaling), skipping Stage 2 and missing out on 50-60% of the heat (and burn time) you'd expect to get from that load of wood. Here's what the US Dept. of Energy website has to say about too-dry fuelwood:
"Some well-seasoned wood can in fact be too dry for today's airtight stoves. If you place wood that is too dry on a bed of coals, it will instantly give up its gases as smoke, wasting unburned smoke and producing creosote buildup."
Stump_Branch
Minister of Fire
I am of the belief that if one extreme is equal to its opposite. meaning, if too wet wood is bad then too dry probably has its pitfalls as well. now that being said hold on. im saying that ranking and stoeing wood outdoors with sun and air for however long, that wood isnt going to get "too dry". mostly because of the environment its in, won allow that. ah the environment now we are on to something. if its kiln dryed or allowed to dry out in something of a 'controlled' environment, then I COULD see the chemical composition changing to produce more 'evil toxins', possibly a fire hazard as the super dry wood could be an uncontrollable fire whatever crap they selling. I know I know Malarkey you say. but when it comes to a one side of the fence or the other...I think ill be someplace in the middle. (or 20% ish in this case)
All good things in life take time. Why wouldnt the same be true for wood?
My guess is you would have to go out of your way, use some sort of energy source, whatever, to make wood 'too dry'.
All good things in life take time. Why wouldnt the same be true for wood?
My guess is you would have to go out of your way, use some sort of energy source, whatever, to make wood 'too dry'.
Kilks
New Member
Stump_Branch said:
I agree with your thinking here - if kept outside wood will always equilibrate with the environment and therefore never achieve these "too low" percentages. Just like with lumber if you want to get down to the 6-7% range you have to bring the air dried wood inside for a while or kiln dry it. It will never happen on its own if left outside.
woodchip
Minister of Fire
There is one other issue to look at.
When designing a wood stove now, would someone deliberately produce one that burns wood at 1% m/c better than 15%?
If most people dry wood to 15 - 20%, would the manufacturers not make stoves that burn wood most efficiently in this range.
Note, this is merely a comment for thought, and not a serious belief.
As I see it any moisture means boiling water and steam in the stove hindering the secondary combustion and the lower m/c, the better, as long as the stove is in good condition and has airtight seals when dialled down
When designing a wood stove now, would someone deliberately produce one that burns wood at 1% m/c better than 15%?
If most people dry wood to 15 - 20%, would the manufacturers not make stoves that burn wood most efficiently in this range.
Note, this is merely a comment for thought, and not a serious belief.
As I see it any moisture means boiling water and steam in the stove hindering the secondary combustion and the lower m/c, the better, as long as the stove is in good condition and has airtight seals when dialled down
Kilks said:
Today's stoves are not the air-tight stoves. This is just one more case of some dummy putting into print something they have read in the past and just pass it along, ignorant of what today's stoves really are like.
woodchip said:There is one other issue to look at.
When designing a wood stove now, would someone deliberately produce one that burns wood at 1% m/c better than 15%?
If most people dry wood to 15 - 20%, would the manufacturers not make stoves that burn wood most efficiently in this range.
Note, this is merely a comment for thought, and not a serious belief.
As I see it any moisture means boiling water and steam in the stove hindering the secondary combustion and the lower m/c, the better, as long as the stove is in good condition and has airtight seals when dialled down
I think today's stoves are built with the concept of % of efficiency ratings. They simply want to burn the stoves as cleanly as possible and still get lots of warmth out of the stove. To do that, I do believe they use kiln dried wood in their testing.
ruth140
Member
i still want to know what the original complaint say to Woodstock that they answered with "your wood is too dry".
was it running too hot, was it running to cold...was the inside of it warped, was there a crack in the stove?? i mean what was the problem?
Just wonderin'
was it running too hot, was it running to cold...was the inside of it warped, was there a crack in the stove?? i mean what was the problem?
Just wonderin'
perhaps petrified wood is the "too dry" kind. I had a gent tell me early in the season that his wood was too dry and gave off no heat so he cut some fresh to mix with it so he could "get some good heat out of it"......I said nothing and tried not to blink (its a sign of weakness).
Kilks
New Member
Backwoods Savage said:
Hi there and excuse the ignorance, but I am new to the game (3 years burning) and have been using an old stove from the late 70's or early 80's so I am not as familiar with all of the new stove designs. I am assuming that the quick release of gas would not be wasted in a newer stove because of the cat which will efficiently trap and burn this gas? I know that in general my stove is probably not very efficient, but would burning wood in the say <10% mc range be even worse for my air-tight stove? Once again, excuse the ignorance if this doesn't make any sense at all! 8-/
Oh Yawn ! Too bad I couldn't have sent you all a piece of my too dry wood from last season,but it burned too fast.Good riddance.
ruth140 said:i still want to know what the original complaint say to Woodstock that they answered with "your wood is too dry".
was it running too hot, was it running to cold...was the inside of it warped, was there a crack in the stove?? i mean what was the problem?
Just wonderin'
Too dry
Go to that link and see post #50.
Kilks said:
Well, once again, I've never had too dry of wood to my knowledge. Other than kiln dried lumber or something like that I see no worries. My cat has at times really glowed bright red but to my knowledge that did no harm. The stove top would usually go up around 700 but that is all. No harm in that.
Kilks
New Member
Very cool but heck I can't ever imagine somebody having trouble burning really dry wood! Out of curiosity I know some of you talk about burning wood that has been stacked for 6+ years and say it only gets better with age. I would love to be in the situation where I am 6 years ahead! Did any of you that burn that really well seasoned wood have a moisture meter and know the mc? It would be interesting to know... At 30% relative humidity and enough time wood can reach an equilibrium moisture content of under 10% For lumber the rule of thumb is one year of air drying for each inch of wood thickness to reach it's equilibrium moisture content so perhaps large splits do take a full 5 or 6 years to get there. Just curious about the numbers you wood nerds have obtained
Although we've burned wood for over 50 years I have never owned nor used a moisture meter. Can't see any use for one.
woodchip
Minister of Fire
I bought my moisture meter 25 years ago when I surveyed our house, there was damp coming from somewhere, and I was keen to sort out where the damp spots were.
We had the house surveyd by a professional, but he never spotted the underground stream nearby.
At least we never go short of water
And having switched from burning wood in an open fire where you chuck as much on as possible and let it all roar away, to a modern woodburner where it burns most efficiently with dry wood and a carefully restricted air flow, the moisture meter came out again. I don't have a huge store of wood yet (even chopping like mad I could never get ahead of the game), and a quick walk round the logs a few days ago with the meter made it easy to pull out the ones that were dry, and those that were nearly dry and could finish off indoors.......but I've had enough of fiddling around trying to find dry wood in the pile.......
Summer Job Number One.......
Proper new wood store with a places for new logs for chopping, ready to season, and then 3 bays for 1,2,and 3 year old wood.
There is no Summer Job Number Two......
We had the house surveyd by a professional, but he never spotted the underground stream nearby.
At least we never go short of water
And having switched from burning wood in an open fire where you chuck as much on as possible and let it all roar away, to a modern woodburner where it burns most efficiently with dry wood and a carefully restricted air flow, the moisture meter came out again. I don't have a huge store of wood yet (even chopping like mad I could never get ahead of the game), and a quick walk round the logs a few days ago with the meter made it easy to pull out the ones that were dry, and those that were nearly dry and could finish off indoors.......but I've had enough of fiddling around trying to find dry wood in the pile.......
Summer Job Number One.......
Proper new wood store with a places for new logs for chopping, ready to season, and then 3 bays for 1,2,and 3 year old wood.
There is no Summer Job Number Two......
ruth140
Member
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