Firewood too dry?!
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It can be if kiln-dried in a dry climate scenario to an exceptionally low mc. Pointdexter found this out with his solar kiln. The wood outgassed faster than the cat could chew through the smoke. If one is burning a resinous wood like gum, eucalyptus, pine, fir, mesquite, etc. and it is below 10% mc, it can be a good combo for a very wild secondary combustion cycle too. However, getting wood to 8% at the core is not easy, especially in a humid climate scenario.
whatyousmokin
Member
I have a Hearthstone Heritage 8024. The owner's manual contains a statement in regards to inappropriate fuel and over-fire; says not to burn kiln dried lumber; so I would assume kiln dried is considered "too dry" and would too easily result in an over-fire situation.
I'll second this, with the caveat that it probably depends on the stove. If you could limit the gas generation enough on the primary side, I think that zero MC is probably ideal, it's just that stoves aren't designed with that in mind, they're designed to function with what they're most likely to be fed - 15-25% fuel, and maybe some 45% until the operator learns that lesson.
I see that effect in my stoves. If we've had a real bad fire season here, I've seen MC readings getting down to 3% on pine and doug fir by the end of it. My Kuuma furnace (basically a tube stove) and my Englander cat stove struggle to burn that without smoking. The cat stove especially can't keep the chimney warm without some air flow up the flue, but if I add primary air, I don't think the secondary air supply is adequate to burn the amount of gasses produced. It's like stuffing a stove or fireplace with cardboard boxes. When you set it off, most of the flame will be where all that smoke finally mixes with enough air - just above the top of the chimney. Burn barrels do the same thing unless they have a lot of air holes in the top half.
Conversely, my fireplace type of stove loves that dry wood. As long as the fire is kept reasonably small, that ample air supply with good flow, and no reliance on secondary combustion makes for a hot, clean, cheery fire.
This may all be true, and I thought more so for cat stoves where residence time in the cat matters to burn what off gases too quickly for the primary flame (I thought tube stoves would be a bit better in being able to do this as the secondary air is proportional to the draft, and thus related to chimney temp, and with a quick hot offgassing dry fire, the chimney temp will go up, so secondary air will go up - but possibly not yet enough).
But I have burned a full load of 2x4 cut offs in my cat stove and did not see smoke.
The most important point is that the OP lives in NY. There is no way that "normal" firewood would ever be too dry here. I.e. wood that has normally dried, not in a (solar) kiln.
I think it's hard to impossible to get below 12%. I've seen 13% pine, and that's the best I've seen.
But I have burned a full load of 2x4 cut offs in my cat stove and did not see smoke.
The most important point is that the OP lives in NY. There is no way that "normal" firewood would ever be too dry here. I.e. wood that has normally dried, not in a (solar) kiln.
I think it's hard to impossible to get below 12%. I've seen 13% pine, and that's the best I've seen.
Yep, equilibrium moisture content is gonna be in the double digits in most areas of the country, save the desert Southwest.
If RockyMtnGriz has that, and he left the 3% splits out long enough, they would re-absorb moisture and get back to his area's EMC.
(broken link removed)
How is this being tested? I have never seen lower than 8% and that is on specially stored, kiln-dried cabinetry wood and flooring.
I live in the Inland Northwest (Rocky Mountain desert) on the valley floor. I didn't know what the moisture content of some wood was so I bought a General moisture meter (as recommended on here). I checked a few pieces of dead-standing splits on the inside that had been drying for a few years.
I think it was lodgepole pine but might have been elm. The moisture meter was getting some readings below 10% (like 7%). What? I must be doing something wrong. The moisture content of the air must be around 10% here in the summer.
I thought, if this wood was going in an EPA wood stove I might need to spray some water on it to get the moisture content up. Or mix it with higher moisture content wood. But it was intended for a masonry heater so I knew the low moisture content didn't matter. I've seen where some have moisture meters that don't read correctly. Maybe mine was reading low. I don't cover my wood stacks anymore.
I think it was lodgepole pine but might have been elm. The moisture meter was getting some readings below 10% (like 7%). What? I must be doing something wrong. The moisture content of the air must be around 10% here in the summer.
I thought, if this wood was going in an EPA wood stove I might need to spray some water on it to get the moisture content up. Or mix it with higher moisture content wood. But it was intended for a masonry heater so I knew the low moisture content didn't matter. I've seen where some have moisture meters that don't read correctly. Maybe mine was reading low. I don't cover my wood stacks anymore.
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Was that measured with the wood near room temp?
(Though your location can indeed result in very dry wood.)
(Though your location can indeed result in very dry wood.)
Hot summer's day - probably 100 F. Chunk of firewood grabbed and split on hydraulic splitter. Moisture meter turned on. Probes stuck in the open face of wood in the middle. I didn't know about the having both of the probes with the grain thing at the time but I don't think it could have made too much of a difference.
I'm always amazed when I go to the coast by the extra oxygen in the air. It is like I'm in a greenhouse. And also by the green life growing everywhere. Whether in the air or ground, water = life. Lack of water = low life.
I'm always amazed when I go to the coast by the extra oxygen in the air. It is like I'm in a greenhouse. And also by the green life growing everywhere. Whether in the air or ground, water = life. Lack of water = low life.
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How does this compare to tractor supply Redstone bricks? I notice I get really good secondary combustion with these. They must be under 10%.
Poindexter
Minister of Fire
The limit I find for my stove is 12-13%. I can burn 13% without too much trouble, and really prefer 14%, but 12%MC and under is just too dry.
I have seen fire killed dead standing down in the low single digits for MC, but I don't like dragging that stuff through the house because 1) it is too dry for my install and 2) getting the black specks back up out of the carpet is a pain in the neck.
I have seen fire killed dead standing down in the low single digits for MC, but I don't like dragging that stuff through the house because 1) it is too dry for my install and 2) getting the black specks back up out of the carpet is a pain in the neck.
For everybody who has asked, the wood was tested legitimately, yep fresh split, center, temperature, prong direction, all that. Now, do I believe the wood is actually that dry? No, I don't. Pushing any measuring device to the edges of its range is the recipe for large errors. Plus, a consumer grade MM is not what I would consider a "scientific instrument". But if you double the readings from 3 to 6%, just to be safe, it's still mighty dry! In this particular case, the wood being so extremely dry by every other form of observation, is what led me to go get the MM just to see what it would read.
I notice there's a pattern to these dry wood reports:
And then, some years there are regular sloppy wet snows through the summer that sticks to everything, soaks in to standing stuff better than rain, and is Mother Nature's fire proofing! Good to have what you need before things turn wet or be at least a year ahead in those!
Lodgepole pine tends to be small diameter, and usually grows with one substantial very deep crack in it, so the standing dead is somewhat pre-split.
I have lived in the southern Cascades, and the Sierras, before meters were a thing, and while the summers are wicked hot and dry, I don't see these reports from there or the West Coast in general. While you sure don't have to season dead wood there after you've spent half the summer fighting to keep it from going up in flames, I think that much larger trees, that don't grow split like lodgepole, and have real bark and sap and the other things lodgepole doesn't, combined with warmish, humid winters, probably limit how dry most of the wood gets, even if it doesn't rain much for years.
And yes, as mentioned above, if it's a year where there's any unfrozen water available in the fall, I can tell that the super-dry wood gains moisture once it's put in the stack. I try to burn what I can of it before it gets wetter, because the heat output is incredible vs. the volume of wood burned. Works great for a small shoulder season fire, but more than just a couple of pieces is more than my cat stove especially can deal with the smoke from.
I notice there's a pattern to these dry wood reports:
- Rocky Mountain region, usually northern
- Lodgepole pine - normally standing dead in the sun
- September/October
And then, some years there are regular sloppy wet snows through the summer that sticks to everything, soaks in to standing stuff better than rain, and is Mother Nature's fire proofing! Good to have what you need before things turn wet or be at least a year ahead in those!
Lodgepole pine tends to be small diameter, and usually grows with one substantial very deep crack in it, so the standing dead is somewhat pre-split.
I have lived in the southern Cascades, and the Sierras, before meters were a thing, and while the summers are wicked hot and dry, I don't see these reports from there or the West Coast in general. While you sure don't have to season dead wood there after you've spent half the summer fighting to keep it from going up in flames, I think that much larger trees, that don't grow split like lodgepole, and have real bark and sap and the other things lodgepole doesn't, combined with warmish, humid winters, probably limit how dry most of the wood gets, even if it doesn't rain much for years.
And yes, as mentioned above, if it's a year where there's any unfrozen water available in the fall, I can tell that the super-dry wood gains moisture once it's put in the stack. I try to burn what I can of it before it gets wetter, because the heat output is incredible vs. the volume of wood burned. Works great for a small shoulder season fire, but more than just a couple of pieces is more than my cat stove especially can deal with the smoke from.
It'd be interesting to get input on this from the manufacturers on here. I'm sure they've played around and have the instruments to really understand what is happening when we burn crispy wood.
brenndatomu
Minister of Fire
Some say there is no "too dry", only dryer than the stove model was designed for, and others say yes, there can be too dry.
I'm personally of the "dryer than the stove was designed for" mindset for any model I've used...unless they're running lambda control maybe...but even some of those have their limits too.
Jotul recommends not burning wood that has seasoned more than 2 years as it hurts the lower end efficiency.
They also recommend no pine etc. I don't get it. In many areas with certain species 2 years isn't enough to get below 20%
JRHAWK9
Minister of Fire
That statement doesn't say much though. Two years in what climate and what species of wood? Two years for red oak in my climate and it won't even be ready to burn.
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