burning green wood question

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

prajna101

Member
Oct 15, 2009
137
Portland OR
I am trying to extend my dry wood supply. I hear lots of mentions about burning wet wood to mix in pallet wood or demensional lumber or such.

So, If I put two equal size chunks in my stove. One is 30% one is 10%. IS that the same as putting two pieces that are each 20%?

Sorry if this is a stupid question, I am trying to problem solve with the aid of beer. Tomorrow it may be more clear, perhaps with the help of your advice.

todd
 
green or wet wood will deposit creosote. Does not matter if you have some dry wood the water from the wet wood still has to be dealt with. We all burned wet wood at some time especially us old time burners with old time smoke dragons. This old idea of extending burn time is when we just let the fire smolder all night. There was some coals in the morning but not much heat was given off.

The fact of the matter is the new EPA stoves will not put up with wet wood. I would only burn wet wood if you have no other way to keep warm. Just burn the good stuff during the day and forget about overnight burns if your supply is going to run out.
 
TriTodd said:
I am trying to extend my dry wood supply. I hear lots of mentions about burning wet wood to mix in pallet wood or demensional lumber or such.

So, If I put two equal size chunks in my stove. One is 30% one is 10%. IS that the same as putting two pieces that are each 20%?

Sorry if this is a stupid question, I am trying to problem solve with the aid of beer. Tomorrow it may be more clear, perhaps with the help of your advice.

todd

You can put some wet in after you have a good hot fire going. I would not try to mix any wet in at start up or at relaod, its just going to eat up alot of energy in the process of drying the wood out, along with forming creosote up the stack. Get that fire hot, then add a couple here and there.

Buy a few Rubbermaid bins at Kmart or such, and fill them with wood and let them in the stove room,. It will dry out faster than sitting outside.
 
I am spitting smaller, and have a ton next to the stove and fan drying.

My question is, if we accept that 20% dry wood is ok to burn. Does it matter if the 20% is per piece or per load?

Would a full load of 20% peices burn as hot and cleanly as a load of half 30% and half 10% (equaling a load of 20% average).

todd
 
TriTodd said:
I am spitting smaller, and have a ton next to the stove and fan drying.

My question is, if we accept that 20% dry wood is ok to burn. Does it matter if the 20% is per piece or per load?

Would a full load of 20% peices burn as hot and cleanly as a load of half 30% and half 10% (equaling a load of 20% average).

todd

The load with wetter wood is not going to burn as hot due to the fact that the a god bit of the energy & heat from the drier wood is going towards drying out the wet pcs. The wet stuff, unless added to an already established HOT fire, is going to dump moisture up the stack, with moisture comes the cause of creosote, especially at the top area & cap where it is now cooled off wet gases & condensation. You may still get build up even adding to hot fires. But this will lessen it to some extent.
So IMO, no it will not burn as hot or efficient as a full load of dry. Think of it this way, if you loaded your clothes dryer with a load of 1/2 damp & the other 1/2 soaking wet clothes, its going to take longer to dry that full load, then if the complete load was all just damp and soaked stuff in there. And hence, more steam out the dryer vent. Same deal with the wet wood.

If that is all you have, then burn it as you need it. But check that cap & flue about once a month till you see how much it is or isn't building up creosote.
It will burn, just not as efficient, and with much more chance of creosote build up.
 
What kind of stove are you running? My guess is the numbers only work on paper, if an EPA stove. Not certain though, 'cause I'm burning a big, black box that probably pre-dates my birth, and would digest seasoned tennis shoes if given the chance.
 
TriTodd said:
I am spitting smaller, and have a ton next to the stove and fan drying.

My question is, if we accept that 20% dry wood is ok to burn. Does it matter if the 20% is per piece or per load?

Would a full load of 20% peices burn as hot and cleanly as a load of half 30% and half 10% (equaling a load of 20% average).

todd

no. from experience, here's what happens: the dry wood burns hot and fast, baking out the moisture of the wet wood, which may or may not burn well after that. You may reduce creosote to some degree this way, but will need to burn wide open, or close to it, most of the way. You will also not likely have much fun. You will not be able to close the primary air as far. Cannot get as hot without running more air, so can't ever be as clean. As was mentioned above, it works a little better to add small splits of wet wood to a load in an already warmed-up stove. Check your chimney regularly. I spent a couple of months with some underdone cottonwood, and vowed never to bother again. I'd rather not burn and just wait until next year. Maybe try a pallet of those North Idaho Energy Logs?
 
Beetle-Kill said:
What kind of stove are you running? My guess is the numbers only work on paper, if an EPA stove. Not certain though, 'cause I'm burning a big, black box that probably pre-dates my birth, and would digest seasoned tennis shoes if given the chance.

I think you'd have a better chance of it equaling out in a pre-epa stove, since it wouldn't care about secondary combustion.
 
I am running a Lopi Answer EPA stove.

So lets take the clothes dryer example. We are really talking water distribution, not quantity. So, if I have a load of clothes that are all damp (20%) it takes X amount of time to dry with X about of water vapor out the exaust. Lets say that the load of damp clothes has 5 gallons of water it it total.

So if you take a totally dry batch of clothes and pour 5 gallons of water on half of it (making it sopping wet) and the other half was dry still and you put it all in the dryer. Would it still take X about of time to dry and x amount of water vapor in the exaust? Or would it be less or more that the first load of evenly distributed water?

I think you may be right in that it works out logically and on paper, but not in real life. I am just trying to figure out why? Or if its true at all.

todd
 
Its not going to kill anyone, but its not the proper method in the wood burning bible. The math you are using will never dry that wood out. Think or read how one BTU is created, then find the amount of BTUS it takes to raise X amount of pounds of water to release it to steam. That will answer how much wood you are putting down the toilet. I would save that wood and let it season for next year. Use your central heat. If times are tough then just burn it, Stay warm and keep cleaning that chimney.
 
My gut says that the problem lies in that the dry wood simply burns up before evenly drying the wet wood. If the everything in the load is 20%, the moisture is removed evenly, but in a 10/30 load, the heat isn't disproportionately focused on removing that extra moisture. The driest wood bakes out, say, 10% from the wettest wood, and then the wet wood still has fairly high moisture, so the primary stays open. Flue gases stay cooler longer. The moisture isn't removed evenly, but from the outside in. seasoning results in more even drying.

Not a wood scientist though...
 
Let me get my wife to answer this- Never tried doing that with clothes, 'cause it's 'toopid!- :roll: This is not an apples-to-apples comparison. Though I've always wondered what bark undies would feel like?! The density, and permeability of the wood is not an equal factor. You can't dip a log split in a bucket of water, and expect it to soak up and be as water logged as a fresh cut split, all things being equal.
 
Yeah, I think that Madrone is probably right too. We will have to see what my sober mind thinks in the morning (ofcourse when I am avoiding doing my job by surfing on this site).

Madrone, I hope you are dealing with the cold well. Makes me think I have been out of the midwest too long when 30 degrees is defined as "arctic blast 2009" by the news. I am taking my wife home to michigan this winter to show her what real cold is.

Just loaded the stove with bear bricks, off to bed. Good night all, thanks for the advice.

t
 
north of 60 said:
I would save that wood and let it season for next year. Use your central heat. If times are tough then just burn it, Stay warm and keep cleaning that chimney.
This was my first thought. Save your good wood for the really cold snaps and let your central heat take care of the milder days.
 
My experience with non seasoned wood is that you only start to get real heat from it at about two hours into the burn. It takes lots of scrap wood, lots of oxygen and lots of firestarters to get it going.
 
TriTodd said:
... If I put two equal size chunks in my stove. One is 30% one is 10%. IS that the same as putting two pieces that are each 20%?

No, it is not the same. There is no good way to mix kiln dried wood with green wood to equal seasoned wood.

Although you cannot burn green wood with no problems, you can minimize the problems caused by burning green wood in many ways:

1) Start your fire with dry wood, and add the green stuff later
2) When you reload, mix dry wood with the green wood
3) Split your green wood into smaller splits
4) Burn with extra oxygen, for example by leaving the side door cracked open for 10 min after adding your green wood
5) Green pine (50% water) is worse than green oak (30% water) ... but pine dries in 6 months, oak in 2 years, so green oak is usually the "problem". I find that pine rounds fall under 30% in one hot month. After a whole summer, the oak still reads 30%, same as it did on the first day. I cannot explain this, but oak seems like it only begins to dry on the second summer. Or my moisture meter is garbage.
6) CHECK YOUR FLUE FOR BUILD-UP OFTEN

I am currently burning 9 mont oak mixed with 9 month pine. Both the oak and the pine are split too thick and cut too long. The wood was intended for my old stove that was less sensitive than my new EPA stove. I have no problem starting the stove on the 9 month pine, after I split it smaller in my garage, although I do have to leave the side door open. When I reload with the 9 month oak I begin to get some smoke (not too bad as long as I crack the side door). There is nothing I can do, so me (and my neighbors) just live with the stink.

I do have about 1 cord of 18 month oak, but I am saving that for the coldest months.

Good luck.
 
TriTodd said:
If I put two equal size chunks in my stove. One is 30% one is 10%. IS that the same as putting two pieces that are each 20%?

Sorry if this is a stupid question, I am trying to problem solve with the aid of beer.

I have no experience trying to figure out the former situation, but plenty with the latter. With enough beer, I will arrive at a solution. By then I will forget what the original problem was, but at that point I am sure to have a new problem.
 
In response to burning pallett,or dimensional scraps, check out the articles from the chimney sweep section here in the forum,,you`ll learn that there are many ways chemicals are introduced to the lumber during processing, starting with lubricants used too prolong blade life,,, the re are many processes depending on the saw mill and its operation. Some of these chemicals may speed up corrosive breakdown within your stoves operating parts
 
30% + 10% doesn't quite average to 20% in the real world, but if it is what you have to work with this year, then you are doing the right thing by mixing them together to extend your supply. If you run out of 10%, trying to burn the wet stuff alone is going to really suck.

If you have an area of your garage, a protected overhang or porch on your house, or even and unused room inside, make a simple wood drying rack from 2x4's and stack some of the wet wood there. It will dry out faster if you are able to stage it inside your house for a couple of weeks before you have to burn. I've done this with wet wood when I was in a jam and I can tell you that it helps.
 
TriTodd said:
Madrone, I hope you are dealing with the cold well. Makes me think I have been out of the midwest too long when 30 degrees is defined as "arctic blast 2009" by the news. I am taking my wife home to michigan this winter to show her what real cold is.

Just loaded the stove with bear bricks, off to bed. Good night all, thanks for the advice.

t

My wife is from Minnesota, and can't stand the slightest cold at all. I, on the other hand, love it. It doesn't seem too bad at 30, but the wind isn't much fun. Wood pile is a little lower than I expected for this time of year.
How are the Bear Bricks treating you?
 
get a good hot fire with a firebox full of seasoned dry wood ,now throw a milk jug full of water in there ..thats basicly what will happen
it can still often burn but burn half as long and half a hot as it could
 
I'm going to go at this from a completly different angle...

A gallon is a gallon. my example...

40 pound load of wood at the typically accepted level of dry wood 20% moisture, or 32 pounds energy and 8 pounds water. Or about a gallon of water.

40 pound load of wood, 20lbs at 30% and 20lbs at 10%, equals 32 pounds of energy and 8 pounds of water, again about a gallon.

Now I know the higher moisture wood can keep a modern stove from secondary combustion, but if you burning the dryer wood with secondaries and are drying some less than ideal wood at the same time..... A gallon is a gallon

Of course getting enough 10% dry wood to mix in would probably be a problem, but that wasn't the question... ;-)
 
Yes, you are correct in that a gallon is a gallon. You'll just have to feed the stove more of the dry wood to balance out the wet wood that will take longer to fully burn. I imagine the overall efficiency of the system will suffer too.

It's like running an engine with bad gas. Yeah, putting in some super octane will help, but until you get all of that bad gas out of the tank, the engine isn't gonna run so hot - no pun intended.
 
Status
Not open for further replies.