Interesting article "Can wood be to Dry"

[pinewoodburner]

Here is an interesting article about the moisture content of wood and EPA stoves.

http://www.woodheat.org/index.php?option=com_content&view=article&id=63&Itemid=73

 

[nate379]

Looks like a load of malarkey to me.

My Dad heats his shop with almost just 2x4s that are tossed from where he works. Never had a problem with it other than it doesn't last long like a nice log of hardwood will... stove has been in that shop since 1990.

 

[Battenkiller]

Here is an interesting article about the moisture content of wood and EPA stoves.

http://www.woodheat.org/index.php?option=com_content&view=article&id=63&Itemid=73

I would call the folks at Woodstock to get their opinion on the matter. ;-)

 

[Bill]

I believe that extremely dry wood can cause an excessively hot fire and possible overfire. Been there done that, especially when you add very dry wood on hot coles. But I still like dry wood for clean wood burning, I age mine 3 or more years, and then store inside. I disagree with the article about dry wood creating smoke, green wet wood smokes. I often check my chimney when outside, to monitor my fire, and I only see heat waves.

That means it's a clean fire, little to no cresote, no moisture, and an efficient burn.

 

[DanCorcoran]

"I disagree with the article about dry wood creating smoke, "

The article used the wrong wording...it should have said that the wood releases gasses, which burn. Solid wood does not burn: the gasses released by hot wood burn (whether dry or green). Green wood produces much more smoke (visible particulate matter) than dry wood.

As to wood being too dry? It depends on the stove. My Shelburne manual specifically states that kiln-dried lumber is an inappropriate fuel which can overfire the stove and void the warranty. Your stove may be different.

 

[oldspark]

"I disagree with the article about dry wood creating smoke, "

The article used the wrong wording...it should have said that the wood releases gasses, which burn. Solid wood does not burn: the gasses released by hot wood burn (whether dry or green). Green wood produces much more smoke (visible particulate matter) than dry wood.

As to wood being too dry? It depends on the stove. My Shelburne manual specifically states that kiln-dried lumber is an inappropriate fuel which can overfire the stove and void the warranty. Your stove may be different.

Really dry wood releases all its gases in a short time causing more smoke is what they were talking about.

 

[Backwoods Savage]

I didn't read the article but it is probably full of Grade A baloney.

As for calling Woodstock, we argue about it as they seem to feel wood can be too dry. I haven't had too much experience burning wood but it has been my experience that the only time wood is too dry is if you are burning kiln dried lumber cutoffs or something like that. As for regular firewood, I have yet to see any that has been too dry. I might add that we burn quite a bit of soft maple and that stuff can really get dry. No problem. I'll continue to dry our wood for many years before burning it and keep right on smiling.

 

[oldspark]

Dennis, I know you have a strong opinion about this but numerous articles talk about wood can be too dry, every time this comes up I try and remember if I have had any too dry wood and I believe I did, some mulberry trees had been cut down and left to lay, all the bark was gone no punk and the wood was very dry and seemed to burn up very quickly especially for mulberry.

 

[Battenkiller]

The article was written by that goofy John Gulland, Canada's leading expert on wood burning appliances. We all know how crazy wood burns up there in the Great White North, not like our wood, which will burn without smoke once it gets dry enough. %-P

 

[Battenkiller]

... numerous articles talk about wood can be too dry...

Articles, schmarticles.... this forum is all about anecdotal info, didn't ya know that, OS? Please, pay no attention to that expert in the lab behind the curtain - he's as full of shite as the Wizard of Oz, eh?

The fact is that the real experts have been busy behind that curtain gathering data that has made the new stoves possible in the first place. They devised the equipment to test emissions, combustion efficiency, overall heating efficiency, which types of wood burn best, and at what moisture contents they burns best at. This info has been used by the industry for years now to build better and more efficient stoves that people buy and bring home and find ways to defeat the design elements that are so essential to the peak operation of these devices. Numero uno in this regard is attempting to prepare wood that is much drier than the standard that these stoves were designed to burn and tested with in the same damn labs that gathered the combustion data in the first place.

A conspiracy by scientists to burn down homes across America? You decide:


How To Control Creosote for Safer Burning

"New scientific research shows that much of what we "knew" was wrong - and even dangerous"

New, as in only 33 years old....

 

[DanCorcoran]

"A conspiracy by scientists to burn down homes across America? You decide:

How To Control Creosote for Safer Burning"



That was an interesting article, but I particularly enjoyed the next one down the page. It was talking about a new technology, soon to be released by Philips NV (in 1980). Something which would reproduce sound even better than cassette tapes and LPs: something called a "compact disc"!

 

[BrowningBAR]

Odd. When I had wet wood I had a ton of creosote build up. When I use dry wood, I get a lot less. I get less smoke with dry wood. Also, starting a fire and maintaining high temps with dry wood sure seem a lot easier on all three types of stoves.

 

[oldspark]

If I understand what BK' point is, some of the issues that get debated on this forum are facts that were discovered 33 years ago.

 

[rdust]

I still maintain outside in a stack with just the top covered you will not have firewood that is too dry. Unless you live in a desert type climate or have kiln dried wood.

 

[dylanmcintosh]

I have a hard time believing this. when i was a kid, my father and I got a maple floor that had been pulled up. put in back in the 90's and sitting there for at least a decade and a half. When we burned that stuff, we had to becareful or our fire would get way to hot for way to long.

 

[iceman]

Wood on the low side of mc along with small splits equals very hot fires, if you read the article he did mention size of the splits... I can personally say that this year has been my best for mc.. but I can't tell you how many times my stove has gone nuclear from putting in medium/small splits.. I have a short stack ~ 14ft. Have checked gaskets ,etc... it the wood.. I think by bringing it in a week ahead of time and inside temps 75 + with low humidity could be lowering it a little bit more...
But I am happy!
Even though I am throwing out a lotta underwear this year

 

[Battenkiller]

Why is it that many folks - particularly Americans - have a hard time believing what the scientists are telling us? I can't tell you how many times I've heard someone say global warming is a myth just because we still see sub-zero days. They (the scientists) even had to stop calling it "global warming" (which is what it really is) and start calling it "climate change" in order to get the message across. And where is that message 5 years after "An Inconvenient Truth" brought it to mass recognition? Same place the creosote issue is 33 years after some dorky science geeks took it upon themselves to actually investigate it. Were they the first "Myth Busters", perhaps? Maybe I should submit it to the show, would anyone believe it then?

If you think deeply into it, there are very clear explanations for every observation that the responders have said here, but none of them can overturn the scientific reasoning as to why they are so. This is not the only study of this sort, just the first (that I know of). I have seen at least six studies that have touched on this issue, and all of them came to the identical conclusions. Seasoned hardwood creates the most creosote per pound of dry wood fiber burned. Ironically, green pine makes the least creosote per pound of wood fiber. Wrap your heads around that concept for a bit.

The new technologies are far better equipped to handle the excessive outgassing (smoking) that putting super-dry wood on a hot coal bed will create, but nothing new in the way wood actually burns has come up since God created the first tree... and the first lightning bolt to ignite it with. There are limits to what these technologies can do. Overcome the available air supply and you have a smoking mess. Overcome the excessive smoke with air and you have a dangerous runaway stove on your hands. Modern stoves work best and at their peak overall efficiency with wood that has a water content between 16% and 20% by weight (19% MC and 25% MC on a moisture meter). Ignore this by trying to get your wood as dry as humanely possible at your own peril.

 

[mtarbert]

I have to disagree with regard to "Powder" cleaners. I sprinkle 4-6 ozs of TSP once a week on hot coals and let it burn away I burn 24/7 and when I check our chimney monthly I have yet to have any creosote. I go through 3-4 cords of good dry hardwood each year.
Just my two cents.

And yes, the next article was interesting. Does it mean the 8 track is on it's way out?

 

[iceman]

Why is it that many folks - particularly Americans - have a hard time believing what the scientists are telling us? I can't tell you how many times I've heard someone say global warming is a myth just because we still see sub-zero days. They (the scientists) even had to stop calling it "global warming" (which is what it really is) and start calling it "climate change" in order to get the message across. And where is that message 5 years after "An Inconvenient Truth" brought it to mass recognition? Same place the creosote issue is 33 years after some dorky science geeks took it upon themselves to actually investigate it. Were they the first "Myth Busters", perhaps? Maybe I should submit it to the show, would anyone believe it then?

If you think deeply into it, there are very clear explanations for every observation that the responders have said here, but none of them can overturn the scientific reasoning as to why they are so. This is not the only study of this sort, just the first (that I know of). I have seen at least six studies that have touched on this issue, and all of them came to the identical conclusions. Seasoned hardwood creates the most creosote per pound of dry wood fiber burned. Ironically, green pine makes the least creosote per pound of wood fiber. Wrap your heads around that concept for a bit.

The new technologies are far better equipped to handle the excessive outgassing (smoking) that putting super-dry wood on a hot coal bed will create, but nothing new in the way wood actually burns has come up since God created the first tree... and the first lightning bolt to ignite it with. There are limits to what these technologies can do. Overcome the available air supply and you have a smoking mess. Overcome the excessive smoke with air and you have a dangerous runaway stove on your hands. Modern stoves work best and at their peak overall efficiency with wood that has a water content between 16% and 20% by weight (19% MC and 25% MC on a moisture meter). Ignore this by trying to get your wood as dry as humanely possible at your own peril.

Well said, I would have thought before that it wasn't possible, but I have seen it first hand. I also believe as you said, our stoves can only do so much. As in my case it was shut all the way down and just kept climbing - slowly

 

[BrowningBAR]

Why is it that many folks - particularly Americans - have a hard time believing what the scientists are telling us? I can't tell you how many times I've heard someone say global warming is a myth just because we still see sub-zero days. They (the scientists) even had to stop calling it "global warming" (which is what it really is) and start calling it "climate change" in order to get the message across. And where is that message 5 years after "An Inconvenient Truth" brought it to mass recognition? Same place the creosote issue is 33 years after some dorky science geeks took it upon themselves to actually investigate it. Were they the first "Myth Busters", perhaps? Maybe I should submit it to the show, would anyone believe it then?

If you think deeply into it, there are very clear explanations for every observation that the responders have said here, but none of them can overturn the scientific reasoning as to why they are so. This is not the only study of this sort, just the first (that I know of). I have seen at least six studies that have touched on this issue, and all of them came to the identical conclusions. Seasoned hardwood creates the most creosote per pound of dry wood fiber burned. Ironically, green pine makes the least creosote per pound of wood fiber. Wrap your heads around that concept for a bit.

The new technologies are far better equipped to handle the excessive outgassing (smoking) that putting super-dry wood on a hot coal bed will create, but nothing new in the way wood actually burns has come up since God created the first tree... and the first lightning bolt to ignite it with. There are limits to what these technologies can do. Overcome the available air supply and you have a smoking mess. Overcome the excessive smoke with air and you have a dangerous runaway stove on your hands. Modern stoves work best and at their peak overall efficiency with wood that has a water content between 16% and 20% by weight (19% MC and 25% MC on a moisture meter). Ignore this by trying to get your wood as dry as humanely possible at your own peril.

The original article states:

The right band of firewood moisture is between 15 and 20%. When you get much over 20% you start to see symptoms of sluggish ignition and the inability to turn down the air without extinguishing the flames.

Your numbers seem a bit high.

 

[Battenkiller]

Your numbers seem a bit high.

???

What... 1% higher on the low range? I am just using the numbers that the EPA testing protocol demands (16-20% wet-basis). No one said wood 1% lower will cause your stove to become either a smoke dragon or a runaway.

 

[BrowningBAR]

Your numbers seem a bit high.

???

What... 1% higher on the low range? I am just using the numbers that the EPA testing protocol demands (16-20% wet-basis). No one said wood 1% lower will cause your stove to become either a smoke dragon or a runaway.

The original article mentions that 15-20% is "the right band of firewood moisture". Which reads to me like the moisture count on a moisture meter. It mentions that "when you get much over 20% you start to see symptoms of sluggish ignition and the inability to turn down the air without extinguishing the flames." The numbers you listed are well into the 20+% unless I am reading it incorrectly.

Modern stoves work best and at their peak overall efficiency with wood that has a water content between 16% and 20% by weight (19% MC and 25% MC on a moisture meter)

 

[Battenkiller]

The original article mentions that 15-20% is "the right band of firewood moisture". Which reads to me like the moisture count on a moisture meter. It mentions that "when you get much over 20% you start to see symptoms of sluggish ignition and the inability to turn down the air without extinguishing the flames." The numbers you listed are well into the 20+% unless I am reading it incorrectly.

The original article began with this:

"Properly seasoned firewood still has a fair amount of water in it, say 15 to 20 percent of its weight."

Moisture meters do not, and never have, given results in percent water by weight. They give results in total water in the wood divided by total weight of pure wood fiber contained within. I have tried my best to distinguish between these two methods of expressing moisture content, there has even been a Wiki entry regarding this. I cannot make everyone understand what seems to me to be a very simple concept merely by repeating it over and over. If you actually take the time to read both the EPA and the Canadian test procedures, you will see that both methods are used to express the required moisture content of the test fuel, but they will specify whether they mean "wet-basis" or "dry-basis" each time, and each time the correct (but different) numbers are used. Again, the meter reads dry-basis and the percent water by weight is a wet-basis (sometimes referred to in the literature as "moist basis") expression. Same amount of water present in the wood, different numbers used to express it. There is no other way I know to explain this difference, feel free to continue to doubt it if you chose.

 

[BrowningBAR]

The original article mentions that 15-20% is "the right band of firewood moisture". Which reads to me like the moisture count on a moisture meter. It mentions that "when you get much over 20% you start to see symptoms of sluggish ignition and the inability to turn down the air without extinguishing the flames." The numbers you listed are well into the 20+% unless I am reading it incorrectly.

The original article began with this:

"Properly seasoned firewood still has a fair amount of water in it, say 15 to 20 percent of its weight."

Moisture meters do not, and never have, given results in percent water by weight. They give results in total water in the wood divided by total weight of pure wood fiber contained within. I have tried my best to distinguish between these two methods of expressing moisture content, there has even been a Wiki entry regarding this. I cannot make everyone understand what seems to me to be a very simple concept merely by repeating it over and over. If you actually take the time to read both the EPA and the Canadian test procedures, you will see that both methods are used to express the required moisture content of the test fuel, but they will specify whether they mean "wet-basis" or "dry-basis" each time, and each time the correct (but different) numbers are used. Again, the meter reads dry-basis and the percent water by weight is a wet-basis (sometimes referred to in the literature as "moist basis") expression. Same amount of water present in the wood, different numbers used to express it. There is no other way I know to explain this difference, feel free to continue to doubt it if you chose.

Yeah. Sorry for asking questions. Won't happen again.

 

[Battenkiller]

Yeah. Sorry for asking questions. Won't happen again.

C'mon, man. Don't take offense, I just get tired of hammering the same point home on thread after thread. It is also very difficult to take this stance, which seems to fly in the face of advise given by some very experienced, well-meaning, and well-respected members here, but I feel morally obligated to bring this to peoples' attention. The whole thing makes me very testy, but I have no choice if I chose to stay an active participant in these discussions. I don't think there's a person on this board who would deliberately give poor or dangerous advise, and I'm no exception. So excuse me, I did not mean to be in attack mode with my comments.

I'm sure that you are burning well within the limits of acceptable moisture content, but the article clearly explains a potential problem, and goes on to state that the new stoves work best within a rather narrow band of water content - plus or minus a few percent around the magic 20% MC range. I am left to assume he means wet-basis when he says that, since that is consistent with the rest of the article and it is the accepted method of expressing moisture content in the hearth industry.

Gulland states he has never seen wood that is lower than 14% water by weight when stored in outside conditions, but in my area wood will eventually reach an equilibrium moisture content (EMC) of 14%. EMC is a dry-basis calculation. A 14% EMC is equivalent to 12% water by weight, so my wood can get pretty dry here all on its own. Another thing to consider is that wood exhibits what is called a "hysteresis effect". That means that wood that is dried straight down to equilibrium with the storage area will have a higher MC than wood that is brought up to equilibrium from a drier (i.e. kiln-dried) condition. So, even stored outside under cover, kiln-dried wood will stay drier than air-dried wood in the same humidity/temperature conditions. That's the danger in the wood stored in barns and such that Gulland mentions. Once it gets way down there in MC, it will never recover to have the same amount of water as naturally seasoned wood will have.

You didn't ask these questions, but I gave you the answers anyway so you won't have to ask. ;-)