wood moisture

It depends on how you measure it. The moisture content is not changing, but the conductivity is changing, so you will see a thermal coefficient if you use a cheap ohmic moisture meter for your testing.

Most conductive/ohmic meters are roughly calibrated to 20C, and will read higher when the wood is warmer than 20C, or lower when it's colder than 20C. I say "roughly", because it varies more widely by species... so unless your meter allows you to select different ranges for different species, its measurement is only a very rough estimate of moisture content. It's usually good enough for a wood burner's requirements, though.

An acceptable correction factor used by some temperature-compensating ohming meters is 0.1% MC per degree-C, above or below 20C.

Using 0.1%/*C, it should read roughly 21% when it finally reaches room temp, assuming I can still do math in my head. Now as to how accurate that measurement is with your meter... that's a whole other debate.

Even without a moisture meter and despite the temperature you can tell pretty well if wood is good to burn. Cracking and splitting on the ends, the overall feel of the weight when you pick up a piece, and especially the feel and smell of freshly split wood are good indicators.

Sorry, but cracking/splitting on the ends is not always a good indicator.
I've got some Oak that I cut down late last year.....very wet, that had some cracking/checking on the ends within a month.
That stuff isn't gonna be ready to burn for a little bit.
The Oak in the shed that's been c/s/s for almost 3 years also has the cracking/checking. That stuff is ready to burn.
Maybe it works better in your climate?

I don't think he was saying cracking on the ends means it's dry. It's just one of several signs you need to see.

Oak does seem to split faster than the rest. I have a whole pile of larger oak rounds sitting in my wood lot, felled three weeks ago, and bucked two weeks ago. They've already got some splits opened up a full inch on each end.

Joful said:

I don't think he was saying cracking on the ends means it's dry. It's just one of several signs you need to see.

Oak does seem to split faster than the rest. I have a whole pile of larger oak rounds sitting in my wood lot, felled three weeks ago, and bucked two weeks ago. They've already got some splits opened up a full inch on each end.

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But that cracking on the ends is something a lot of folks like to quote and state that it shows the wood is dry. Dave was correct. The cracking on the ends of the logs shows only that the ends are drying. It says nothing about what the inside of the wood is like.

All that's true, the checking on the ends is just one indicator. Splitting the wood and checking the inside of the split with a moisture meter is the best, but feeling the moisture and smelling the aroma of the wood on a fresh split works well too. If you're used to how heavy a dry piece of the same type of wood feels, the weight of a moist piece will feel al lot different also.

Joful said:

They've already got some splits opened up a full inch on each end.

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But, I bet they aren't dry......just dry-ing. Might not be ready to burn either.
Well, not enough so that I'd want to burn 'em. Been there and done it.

PapaDave said:

But, I bet they aren't dry......just dry-ing. Might not be ready to burn either.
Well, not enough so that I'd want to burn 'em. Been there and done it.

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Oh, definitely not! 30" diameter oak rounds don't dry in 3 weeks! :lol:

Wood Heat Stoves said:

If you're used to how heavy a dry piece of the same type of wood feels, the weight of a moist piece will feel al lot different also.

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I've had pretty good luck so far with that approach -not 100% but not too bad...

OK, so I've got some wood that smells like pine, has cracking on the ends, and is kind of heavy, but not real heavy, and when I bang two pieces together it sort of goes clunk! clunk! What would the moisture content be with wood like that?

Lumber-Jack said:

OK, so I've got some wood that smells like pine, has cracking on the ends, and is kind of heavy, but not real heavy, and when I bang two pieces together it sort of goes clunk! clunk! What would the moisture content be with wood like that?

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Pine constantly amazes me at how fast it dries out. I got a cord of ponderosa a month ago...split it immediately and stacked it. A few of the thinner splits are already about 27%. Crazy fast drying wood.

When the end cracks are wide it says, "wet on the inside" - as they close back up your wood is getting dry through and through. Wood that has been seasoning for years will show checking but no where near as prominant as wood that has been seasoning for 6 months.

Lumber-Jack said:

OK, so I've got some wood that smells like pine, has cracking on the ends, and is kind of heavy, but not real heavy, and when I bang two pieces together it sort of goes clunk! clunk! What would the moisture content be with wood like that?

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27.67352%.
Let it sit for another couple days and if it IS pine, you're gooder to go.
Joking, of course. Needs at least another week. hehehe

PapaDave said:

27.67352%.

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WOW! so that sniff and bang method really is very accurate. Guess I'll throw my moisture meter away, because it's telling me something totally different.

Here in California, it's so hot and dry that a soft wood like Pine will season in a Summer (about 4 mo) if it's split and stacked, Oak a year. Other parts of the country that are more humid can take a lot longer. I can feel the difference in weight between the unseasoned stack and the seasoned stack of the same type of wood just by picking it up. The proper way to measure moisture is to split the wood and stick a moisture meter into it but not everyone has one. I make sure I've seasoned it long enough before I even try to burn it and then I mostly sort it because some pieces get wet from rain or snow seeping in.

Wood Heat Stoves said:

I can feel the difference in weight between the unseasoned stack and the seasoned stack of the same type of wood just by picking it up

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Man, I wish I could pick up a stack of wood.
Filling the shed would be sooooo much easier.

wingsfan said:

I know wood will give you a different moisture reading depending on if it is cold or room tempeture, But what is the diferance? If you get a certain reading while the wood is cold, will it read less or more when the wood is at room temp?I'm guessing it would be lower at room temp., but just trying to find out for sure.

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Check out this thread Played with my moisture meter today

Wood Heat Stoves said:

Here in California, it's so hot and dry that a soft wood like Pine will season in a Summer (about 4 mo) if it's split and stacked, Oak a year. Other parts of the country that are more humid can take a lot longer. I can feel the difference in weight between the unseasoned stack and the seasoned stack of the same type of wood just by picking it up. The proper way to measure moisture is to split the wood and stick a moisture meter into it but not everyone has one. I make sure I've seasoned it long enough before I even try to burn it and then I mostly sort it because some pieces get wet from rain or snow seeping in.

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Here in humid Michigan pine can dry pretty fast too. I cut two large limbs off a white pine in early December. These limbs came down in a July windstorm. The wood was all extremely dry and right now they are being burned for boiling maple sap.

PapaDave said:

Man, I wish I could pick up a stack of wood.
Filling the shed would be sooooo much easier.

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It really helps dry the wood faster, too. I just pick up the stack and move it around so it stays in the sun all day. It's good to be strong.