Moisture Content... How dry is too dry?

[sean b]

I always figured I was seasoning my firewood long enough before burning but never bothered to pick up a moisture meter until today (after reading the thread from Fiona). So I took a piece of pin oak and locust from the stack that I moved from the outside pile (under shelter) into my garage and checked it after splitting each piece again. The oak was 14-15% and the locust was 10%. This wood has been sitting under roof in open air for the better part of 3 years. I read somewhere here that wood that is too dry can also be an issue. Can someone explain?

Thanks!

 

[SteveKG]

In my area, it is not uncommon for us to have rel. humidity at less than 10%. I've seen my firewood that low and lower. In 40 years and a number of stoves, I have had zero problems with burning wood that dry. I doubt I ever burn wood that is greater than 12 to 15%. Usually at the low end of that.

 

[bholler]

The oak was 14-15% and the locust was 10%. This wood has been sitting under roof in open air for the better part of 3 years. I read somewhere here that wood that is too dry can also be an issue. Can someone explain?

I think you are getting bad readings on the locust the oak could be right but in central pa but i seriously doubt you could get 10% air drying. And yes 10% could cause trouble by off gassing to quickly if that is the actual moisture content,

 

[sean b]

What problem does off gassing too quickly cause?

 

[bholler]

What problem does off gassing too quickly cause?

Possibly over firing

 

[Seanm]

Cant speak for oak but pine has this problem. The off gassing can be so pronounced that it causes large amounts of smoke that cant be reburned so it floats around the firebox making everything black including the glass and then belches out the chimney even at high stove temps. Pine so dry the moisture meter wouldnt pick up a reading. Ive never heard of this problem with harder woods though.

 

[FionaD]

I'm burning Eco bricks at the moment that have an MC around 10%. They off-gas easily, for sure, but not too fast for the secondaries to ignite. I just know I need to dail out the primary air a lot faster after a reload, to stop everything burning too hard and fast.

So I can't see why such a low MC might be viewed as bad for wood but OK for an Eco brick - unless I'm missing something...

 

[crater22]

Replying just to check more responses, as I am burning Ash in 5 inch splits that weigh about the same as a pencil. MM reads about 12% on average.

 

[saskwoodburner]

As long as a guy/gal understands the different burning characteristics between 10% wood and 20% wood, you should be alright. You gotta get the air shut down fairly quick on that super dry stuff.

 

[jophysx]

I doubt there is any problem with "too dry" wood that can't be taken care of by adjusting your burning habits. In general, the energy spent vaporizing the moisture in the wood is energy that won't help heat your house.

 

[jophysx]

Super dry combined with very small splits could be a challenge, but I would turn that around as an opportunity to move to large splits.

 

[begreen]

We're burning some super dry doug fir right now. It's easy to start fires with full 6" splits. But the burn times suffer a bit. Even with the air closed all the way down this stuff wants to burn quickly. Once I am through this cord we will be into 9 month seasoned fir which should help lengthen burn times.

 

[Poindexter]

I have heard via pm from bkvp that wood in the 8-11% can be a problem in catalytic stoves. As above wood that dry can off gas enough crud fast enough to overwhelm the cat.

I burnt plenty last year at 12% with no trouble.

I have cocktailed stove loads to bring the average mc in the box down, that is made a point to load some dryer wood to help get wood that is a little too wet burning well. Its a pain in the neck.

Makes sense that tou could load some wetter wood in each load to make up for wood that is too dry, also sounds like a pain in the neck.

Ideal for my stove, my install is 12-16% per handheld gizmo.