Too seasoned?

mar13

Member
Nov 5, 2018
170
Humboldt coast, California
Highbeam made a comment in another thread where he said he was thinking wood can be too dry. That had me think back to my puzzlement over the following statement from a Jotul manual I read on the web. From Jotul manual: "Wood that has been air-dried for a period of 6 to 14 months will provide the cleanest, most efficient heat. Wood seasoned more than 2 years will burn too quickly to take advantage of the stove’s low end efficiency strength."

Now, I'm not talking extremes here. Not wood that is sitting in the high desert for a long time or some softer wood like alder than doesn't seem to age well. Or wood that is kiln dried to sub 10% mc. But what about, say, oak that is stored outside in a shed? I have oak that is probably 4-5 years seasoned. Am I losing significant BTU just from time alone while it sits in the stacks? (Perhaps oxidation -just throwing that word out with knowing its true meaning - if that's possible with wood?) Maybe Jotul is talking about birch or some softer hardwood found in Norway, as I think is true with Alder?

I do know, I'd rather error on the dry rather than moist side.

Anyhow, this post is from somebody who used to think the older the wine the better...
 

weatherguy

Minister of Fire
Feb 20, 2009
5,388
Central Mass
Depending on where you live it's only going to get so dry being outside, top covered. If you put it a kiln say a solar kiln it could get too dry and not burn as efficient as the stove is designed. Your oak should be ok.
 

begreen

Mooderator
Staff member
Nov 18, 2005
79,245
South Puget Sound, WA
Wood will eventually settle depending ambient humidity. Early this spring I tested a doug fir split that is 3 yrs old vs a split that is 1 yr old. Both were in the 17-18% range. As I noted in the Jotul thread I think Jotul must be referring to very thin splits. A 4"+ oak split is going to take some time to dry. And as damp as the east coast has been 2 yrs is the norm.
 
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Kevin Weis

Minister of Fire
Mar 3, 2018
844
Union Bridge, Md
Apparently there is such a thing as too dry wood as it would off gas to fast to be pulled through the stoves cat and burned that instead accumulates in the firebox and "explodes" there creating back puff conditions (smoke in the room). This is more of a danger I think if the splits are small in size.
 

lsucet

Minister of Fire
May 14, 2015
1,573
San Ysidro, New Mexico
I don't know on different stoves but on mines is normal to burn pine that is 7 to 8 % of MC and the experience is quite good. Initial hot burn, dial it low and the cat gives good heat and when the thermostat opens the cat brings back to temp everything quick. I think is related to not too much moisture to deal with and most is BTUs.
 

Woody5506

Minister of Fire
Feb 14, 2017
709
Rochester NY
I've heard of the "too dry" theory but meh, I'd rather burn too dry than too wet.

One of the best fires I ever had in my T5 was with some ash that was near 20 years split.
 
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Alpine1

Feeling the Heat
Apr 27, 2017
305
Eastern Alps, Italy
Every % increment in relative humidity decreases stove BTU output. The drier the better, unless we’re talking old fashioned wood stoves without cats or secondary burn sistem. In that case, the super dry wood can off gas faster than the wood stove ability to burn the released combustible. But I don’t think that’s the case. I totally agree with the OP, I’d rather error on the dry side than the moist one.
 
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johneh

Minister of Fire
Dec 19, 2009
2,341
Eastern Ontario
Never had it to dry the drier the better . I have burnt
cut offs a waist wood from my wood shop at 6 to 8 %
Kiln dried no problem. Never heard of wood being to dry
Now to wet !!!!!!!
 

Dobish

Minister of Fire
Oct 26, 2015
1,990
Golden CO
I have definitely noticed with my stove that if it is super dry, I get a lot of puff back and it will burn really hot for a while then puff back. I had a load of cedar and pine that got my temps as high as I have ever seen them in the Cat, and it was hard to control. It also didn't burn for super long.
 

lsucet

Minister of Fire
May 14, 2015
1,573
San Ysidro, New Mexico
I had a load of cedar and pine that got my temps as high as I have ever seen them in the Cat, and it was hard to control. It also didn't burn for super long.
Possibly related to how different stoves handle low MC wood. That is what I burn, 70 to 80% softwood and kind of dry cause in the area I live it can get real low on MC. No problems here controlling it plus getting decent amount of hours of usable heat.
 

Dobish

Minister of Fire
Oct 26, 2015
1,990
Golden CO
Possibly related to how different stoves handle low MC wood. That is what I burn, 70 to 80% softwood and kind of dry cause in the area I live it can get real low on MC. No problems here controlling it plus getting decent amount of hours of usable heat.
Once it off stabilized it was fine, but I was looking at roughly 6 hours compared to 10 for higher MC wood. I found that I would get much longer burn times if I mixed in a little bit of less dry wood.
 

heavy hammer

Minister of Fire
Jul 18, 2015
1,483
Kirtland Ohio
I think the drier the better. You would think that a certain point the wood will only be able to get so dry unless other factors are thrown as stated above. Just my thought.
 

Woodsplitter67

Minister of Fire
Jan 19, 2017
1,099
Woolwich nj
You can have wood that is to dry. I let my wood sit in the kiln one year to long. My cherry was at 2% MC and also my oak was sub 10%. The wood went up quick, and it was hot. I think the optimal rangeis like 18 to 14 % mc.
 
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heavy hammer

Minister of Fire
Jul 18, 2015
1,483
Kirtland Ohio
I have never used a kiln before so I would agree with Woodsplitter67 in this case you probably could have wood to dry. I was just assuming if split and stacked and out in the elements the wood will only become so dry.
 

Highbeam

Minister of Fire
Dec 28, 2006
16,361
Mt. Rainier Foothills, WA
I think my problem was top covering stacks on pallets. The sides always get wet because wind and because water runs off of the top cover onto the sides of the stacks. Each year the wood would get dry but the winter wetness caused a sort of punkiness. Old wood was very dry but very light weight having lost mass.

Maybe staying totally dry in my shed there will be no such thing as “too old”.
 

hickoryhoarder

Feeling the Heat
Apr 5, 2013
304
Indiana
I don't know that it gets too dry, but firewood can deteriorate by the 4th or 5th year.
 

Highbeam

Minister of Fire
Dec 28, 2006
16,361
Mt. Rainier Foothills, WA
I'd think there would be some science out there to explain why and how much.
Vast amounts of experience, decades for some folks, trumps what very little actual science is involved here. The key thing is that a stack of firewood out in the yard is usually much less protected from the elements than the lumber in your home’s walls.
 

mar13

Member
Nov 5, 2018
170
Humboldt coast, California
Vast amounts of experience, decades for some folks, trumps what very little actual science is involved here. The key thing is that a stack of firewood out in the yard is usually much less protected from the elements than the lumber in your home’s walls.
Yes, I'm sure that many 100+ year old wood homes have given plenty of heat when burning down.
 
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blades

Minister of Fire
Nov 23, 2008
3,333
WI, Leroy
and they go up real fast
 

Sawset

Minister of Fire
Feb 14, 2015
572
Palmyra, WI
Wood seasoned more than 2 years will burn too quickly to take advantage of the stove’s low end efficiency strength
This makes sense to me in that wood too dry would burn too intensely. Moisture would have a dampening effect. If the stove is efficient at low burn rates, that low rate would never materialize since the fire would be difficult to control to that low level.

Am I losing significant BTU just from time alone while it sits in the stacks? (Perhaps oxidation -just throwing that word out
Interesting. Wood seems to become brittle with age if kept under cover for a long period, like some form of deterioration or hardening has taken place. It seems to split easily (nailing etc), and takes on an aged coloration, similar to how paper does with age.
But consider a tree though - could be several hundred years old, consistently surrounded by water, and the heartwood has remained at high moisture the entire time. Yet it has been excluded from free air and drying. What else is in there besides water? A lot of volatile aromatics, terpenes, and a very long laundry list of others. A lot of those would give off BTU's if they had been burned. And I bet a lot of those leave over time as wood is aged open to the air. This is all just a guess.
Vast amounts of experience, decades for some folks, trumps what very little actual science is involved here.
 

lsucet

Minister of Fire
May 14, 2015
1,573
San Ysidro, New Mexico
This makes sense to me in that wood too dry would burn too intensely. Moisture would have a dampening effect. If the stove is efficient at low burn rates, that low rate would never materialize since the fire would be difficult to control to that low level.
It depends the stove in use. I burn real dry wood here in this part of the country, pine being the main species. It gets real low in MC, no problem at all controlling the fire with full load.;)