The importance of seasoned wood - Dry vs Wet

[Dennis72]

I filled the wood rack yesterday. The wood has been on this truck for three years...sitting in the machine shed. I'm pretty sure it's ready to burn.

 

[Nordicbynature]

How bad is 27% MC?

Sold 1.5 cords unseasoned wood (aspen / populus tremula ) to a guy and told him he can use it winter 26/27. It had 27% MC when I split it.

Got a message, that the wood is drying well (we have a golden autumn) and he wants some more. Got the feeling he might want to burn the wood already this winter.

Went to his house re-split some pieces and measured 27% MC. The outside surfaces had in fact dried to around 15%.

So how bad is it to burn a cord of 27% MC wood? The guy has a good and efficient secondary burner.

 

[begreen]

It's not ready to burn when over a quarter of the wood weight is water. That's asking for creosote problems.

 

[30WCF]

7% away from 20. It’s relative. Some stoves won’t hate it. Others will choke. You might be ok’ish with a tube stove, you will choke out a newer cat. An old smoke dragon may not even know it’s burning it.
Outboard boat motors go from 2hp to +\-500hp or so. Years ago I took off an 18 hp from my skiff and put a 25 hp on. Who cares about 7hp? I don’t know, but I know who cares about a 28% increase in power.

 

[Nordicbynature]

It's not ready to burn when over a quarter of the wood weight is water. That's asking for creosote problems.

How about pollution, particles, NOx and so on?

 

[brenndatomu]

The only way 27%mc wood will not cause problems is if he burns hot n hard! Highly unlikely they will be though.
So think of it this way...27% by weight is water...so in a 50# load of wood (possible in a larger stove) there is almost 1.5 gallons of water! Doesn't sound like good firewood to me!

 

[NickW]

How about pollution, particles, NOx and so on?

Also will be worse. Moisture creates steam which reduces combustion and temperature creating more volatiles going up the chimney at a lower temperature producing creosote and emissions.

 

[sixer]

The only way, maybe, would be to split them smaller and stage the pieces in front of a hot stove w/ blowers on for as long as possible. 27% seems pretty bad though. If they were low 20's, or only a few of the pieces were high with the rest <20% the method above would be more effective.
Let's complicate this further, shall we?!
I have this chart I found long ago:

If the moisture meter was calibrated for say, red oak, then 27% is about 400k ohms. For Aspen (the wood in question - though not sure about "bigtooth") 400k ohms is more like 23%... As they say, "your mileage may vary".
Regardless, hissing and smoking wood is bad.

 

[Todd]

How bad is 27% MC?

Sold 1.5 cords unseasoned wood (aspen / populus tremula ) to a guy and told him he can use it winter 26/27. It had 27% MC when I split it.

Got a message, that the wood is drying well (we have a golden autumn) and he wants some more. Got the feeling he might want to burn the wood already this winter.

Went to his house re-split some pieces and measured 27% MC. The outside surfaces had in fact dried to around 15%.

So how bad is it to burn a cord of 27% MC wood? The guy has a good and efficient secondary burner.

I burn lots of Aspen, it drys fast. I’ve cut it in spring and it’s ready by Fall. At 27% it’s possible it will be ready in a 2-3 months if stored properly.

 

[Nordicbynature]

The only way, maybe, would be to split them smaller and stage the pieces in front of a hot stove w/ blowers on for as long as possible. 27% seems pretty bad though. If they were low 20's, or only a few of the pieces were high with the rest <20% the method above would be more effective.

Thanks. But i want to explain to the guy, why he should not burn it until the following winter 26/27.

 

[Nordicbynature]

I burn lots of Aspen, it drys fast. I’ve cut it in spring and it’s ready by Fall. At 27% it’s possible it will be ready in a 2-3 months if stored properly.

Yeah, seems to be good stuff. Very easy to work with. Easy to saw, cut and split.

Energy content should be similar to fir, but clean burning.

It is used to make matches in Sweden.

 

[sixer]

I've found aspen to dry pretty quickly also. I used it as a starter wood in shoulder season a couple years ago. It burns pretty fast and doesn't do much coaling from what I remember. It's kind of a soft hardwood if that makes any sense. That was before I got a moisture meter. I have a few more aspen I'll be taking down once the leaves come off. I'll try to remember to take some readings.

As far as what to tell the guy, just go with the truth. Say it's probably not ready for this year and if it smokes and hisses he's asking for trouble (and not burning efficiently). If he's gonna do it anyway, well you can lead a horse to water...

 

[EbS-P]

Got the feeling he might want to burn the wood already this winter.

Went to his house re-split some pieces and measured 27% MC. The outside surfaces had in fact dried to around 15%.

So how bad is it to burn a cord of 27% MC wood? The guy has a good and efficient secondary burner.

If it’s his first winter with a wood stove ask if he’s the only one tending it. My wife about call the installers to come and take it back because it didn’t throw heat or burn wood. It’s not worth the hassle. If he wants to burn this year he’s better buying compressed saw dust bricks.

 

[begreen]

How about pollution, particles, NOx and so on?

Yes, that will be higher. Creosote is formed by the condensation of these items.
Lower heat output will be another direct result. A lot of people blame their stoves as not working when the problem is often the wood or the operator.

 

[Todd]

I measured a couple splits of my Aspen that have had two summers to dry and it was at 12%. I think this is on the verge of too dry. Burning it the last couple nights it really off gasses fast and I have to shut the stove down very quickly. Not ideal for burning later this winter but it works fine this time of year.