How to test for moisture in my wood stack

ezwryder said:

When I split my wood, I check moisture content and stack accordingly. After time goes by and I want to check moisture content again, do I have to split it again or can I just stick my moisture meter prongs into the end of the split and get an accurate reading?

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You want to know the moisture content within, not on the exterior, so you should check moisture on a freshly split surface.

You can get a pretty good reading by grabbing a stick from down in the pile and sticking the probes into the midsection, oriented lengthwise.

We are dealing with approximations here.

One useful visual check: Drying is happening near the surface when checking shows up on the ends; drying is happening in the innards when the end checking closes.

You need to freshly split it. Wood can seem very dry on the outside, especially on a piece that has been split before, but I've split wood again and felt and smelled the moisture inside before even checking with a moisture meter.

CTYank said:

One useful visual check: Drying is happening near the surface when checking shows up on the ends; drying is happening in the innards when the end checking closes.

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Have any pictures?

I think hes asking if he has to split the split again or maybe try another split. My guess is you would have to try another split as the already split, split will be drier on the outside.

Wood Heat Stoves said:

You need to freshly split it.

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Period. Exclamation mark. Reading the ends with a meter will tell you nothing other than the ends are getting dryer, and reading the long-exposed side of a split will tell you nothing other than the wood is drying from the outside in. No surprise in either case, and no useful information. Select a substantial piece of the wood from the stack, split it, then measure on one of the freshly split faces. That's useful information. Rick

BrotherBart said:

Actually if I get curious I just chuck a small bit in my cordless drill and poke two holes in the middle of a split and stick the meter prongs in it. Several years ago I re-split a couple after doing that and the reading was the same.

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Or you can get one of these guys:

Remmy122 said:

CTYank said:

One useful visual check: Drying is happening near the surface when checking shows up on the ends; drying is happening in the innards when the end checking closes.

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Have any pictures?

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Not of the type you probably seek; just the word-picture above, which I hoped covered it. Restating:

Fresh-cut piece typically will have no cracking/checking on the end.

As they start to dry, depending on species, cracks on the ends will open up to about 1/8" wide.

As the innards of the splits dry, the stresses inside the wood near the butt faces will decrease and the cracks will close, often simply going away.

Then you're into serious overall drying. (The above is from experience with stacks having shed-roof above.)

All this stuff about "gotta resplit" IMHO is pseudo-precision, maybe even OCD, when all you'd need is a good approximation of the MC, which I've found you get from checking on a face that's been "sheltered" in the stack. Toss in leaving stacks uncovered, and you've got some serious "known unknowns" and mega-pseudo-precision.

Leave the stack 2-3 years and then check by placing said wood inside your stove and light it. This is a foolproof method of checking to see if the wood is dry enough to burn.

Or better yet, just cut only standing dead trees, like I do, that are already well dried, then you don’t have to wait 2-3 years or watch end cracks open and close.

Seems like everybody has there own unique system for obtaining dry wood. ;-)

CTYank said:

All this stuff about "gotta resplit" IMHO is pseudo-precision, maybe even OCD, when all you'd need is a good approximation of the MC, which I've found you get from checking on a face that's been "sheltered" in the stack. Toss in leaving stacks uncovered, and you've got some serious "known unknowns" and mega-pseudo-precision.

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I don't believe that one of those "sheltered" splits will have the same reading on the outside that it would have if you checked a re-split face, at least not until the wood has been sitting for a very long time. At that point it will be "Savage" dry anyway, so what would the point be in measuring it in the first place? If there was that much difference between the splits on the inside of the stacks and the ones on the outside, the wood isn't drying at all inside the stack except for at the ends, and we all know that's simply not true. Plenty of air passes through the stacks, and moisture is continually being carried away with that air.

I have shown this to myself last year when I dug out a few splits of cherry (uncovered, but stacked in the sun and wind) and measured the outside MC. IIRC it was down around 12% MC. When I re-split those pieces, MC was well above 25% inside. I don't look at it as pseudo anything, or even that precise. You are just trying to see if you are near the acceptable range, but unfortunately, you have to re-split the wood to get that approximation. Wood that shows 12% on the outside when it is 25% on the inside can give you a very wrong idea about the present quality of your fuel.

So when you guys are moisture testing a freshly split piece of wood (that had been drying for a while) do you normally find a gradient of moisture readings? What I mean is.. as mentioned above a 12% reading along the edge of the piece with each reading higher as your approach the middle of the split? How do you determine what the average moisture content is then? Add the highest and lowest readings and divide by 2? I would think 25% in the middle and 12% outside would be burning great at with under 20% average moisture content overall.

Carbon_Liberator said:

Or better yet, just cut only standing dead trees, like I do, that are already well dried, then you don’t have to wait 2-3 years or watch end cracks open and close.

Seems like everybody has there own unique system for obtaining dry wood. ;-)

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Just cut down a standing dead tree and mm read 33% I would have swore this one would be dry, but no, woodpecker holes all in it bark was all gone probably been dead 5 or 6 yrs, I don't think they dry, before they rot, not in the trunk anyway.

ezwryder said:

When I split my wood, I check moisture content and stack accordingly. After time goes by and I want to check moisture content again, do I have to split it again or can I just stick my moisture meter prongs into the end of the split and get an accurate reading?

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Yes split another each time you want to check, when I first bought a MM I checked my wood and Was so proud I could dry wood in 3 months at my place. I posted this proud finding on here and was told resplit then check well my 17% went to 30%.

CJRages said:

So when you guys are moisture testing a freshly split piece of wood (that had been drying for a while) do you normally find a gradient of moisture readings? What I mean is.. as mentioned above a 12% reading along the edge of the piece with each reading higher as your approach the middle of the split? How do you determine what the average moisture content is then? Add the highest and lowest readings and divide by 2? I would think 25% in the middle and 12% outside would be burning great at with under 20% average moisture content overall.

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Wood always dries along a moisture gradient, so there is something to what you say, but you can't just assume that the gradient will be uniform throughout the thickness. As an extreme example, if you placed a large green split into a very hot oven, it would get very dry on the outside and yet be completely wet just to the inside of the dry zone. Same thing happens with the Sunday roast or a baked loaf of bread, which get a dry and crispy crust on the outside but stay moist all the way through.

The hammer probe pictured in my post above is what pros use to determine the actual moisture gradient. The probes are insulated except at the tips, therefore, they only read the MC at the very deepest section of penetration. Two or three progressively deeper readings are taken, and the results are used to determine the gradient and the average MC of the piece in question. This is very important in the pulp industry since they are paying for wood fiber, not water in the wood.

I am in agreement with you about the way the wood will burn in your stove, however. Wood that is 12% MC on the outside and 25% on the inside is fine to me. Besides, because of the way meters are calibrated, a reading of 25% on the meter means the wood is only 20% water by weight. Yep, that old wet-basis/dry-basis can o' worms. ;-)

Wood Heat Stoves said:

You need to freshly split it. Wood can seem very dry on the outside, especially on a piece that has been split before, but I've split wood again and felt and smelled the moisture inside before even checking with a moisture meter.

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Here is a picture of what you're describing. This is a live oak round that was split after about eight months. The lighter colored wood at the bottom left was very dry but the darker portions didn't seem to have lost much moisture at all.

Take a piece, measure the outside without splitting it and then split it and measure the inside. Try that on a few pieces and the answer it gave me is you always need to fresh split it.
Enjoy

Carbon_Liberator said:

Or better yet, just cut only standing dead trees, like I do, that are already well dried, then you don’t have to wait 2-3 years or watch end cracks open and close.

Seems like everybody has there own unique system for obtaining dry wood. ;-)

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I've felled standing dead water oaks on my property that were so dead most of the branches had fallen off but water almost runs out of the trunk. Moisture Meter gauge is off the chart. I don't think "standing dead" is a good measure of how seasoned the wood is. Splitting, stacking, and sitting for a long time is what does it.

Yes, exactly- this is what I have seen so many times when splitting deadwood Oak. Looks dry outside, but turns out to be very wet on the inside. That split looks like it will need a year, probably lots more to be truly ready. Of course you'd probably want to split it smaller than halves like that. Almost seems like Oak that is never split would never season. Ever. Not the big pieces, anyway.

trailmaker said:

Wood Heat Stoves said:

You need to freshly split it. Wood can seem very dry on the outside, especially on a piece that has been split before, but I've split wood again and felt and smelled the moisture inside before even checking with a moisture meter.

Click to expand...

Here is a picture of what you're describing. This is a live oak round that was split after about eight months. The lighter colored wood at the bottom left was very dry but the darker portions didn't seem to have lost much moisture at all.

Click to expand...

Backwoods Savage said:

Leave the stack 2-3 years and then check by placing said wood inside your stove and light it. This is a foolproof method of checking to see if the wood is dry enough to burn.

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Leave some larger than desired splits when splitting. I split these to check. So if its 38% when put up. Then you split one of the massive "Double Size" splits and its about 20% on the M/C. Then you know the wood you split to your regular stove size, should be at least that, or Lower. Thats what I have been doing.

Kenster said:

Carbon_Liberator said:

Or better yet, just cut only standing dead trees, like I do, that are already well dried, then you don’t have to wait 2-3 years or watch end cracks open and close.

Seems like everybody has there own unique system for obtaining dry wood. ;-)

Click to expand...

I've felled standing dead water oaks on my property that were so dead most of the branches had fallen off but water almost runs out of the trunk. Moisture Meter gauge is off the chart. I don't think "standing dead" is a good measure of how seasoned the wood is. Splitting, stacking, and sitting for a long time is what does it.

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I agree.
I wasn't trying to say all standing dead are dry, in fact in very moist climates I would think it would be hard to find any standing dry trees at all, but I live in a very dry climate and have access to lots of a particular type of standing dead tree that are very dry, so naturally those are the ones I go after for my firewood supplies rather than green wood that needs years of seasoning time.
If your wood is already dry, then there is no need to check the moisture, that's the point I was making.