MM pins with the grain or across?

  • 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.

BillsWS

Feeling the Heat
Dec 20, 2011
275
U.P. Michigan
In this seasoning firewood video from Portage & Main, he instructs to have moisture meter pins "cross" grain. I was under the impression that placing the pins "with" the grain was correct. Which is better?

 
I do both, and never noticed a difference
 
I haven't watched the movie, but if he's advising to place the pins across the grain so that they bridge between growth rings then he's doing it wrong. With the grain is correct, though as BB noted, it usually doesn't make much difference. To back this up, see page 14 of the USDA / Forest Service document on the topic:

With conductance meters, however, the electrode should be oriented whenever possible so the current flows parallel to the grain. At moisture levels below about 15 percent, the effect of grain direction is negligible. At moisture levels above 20 percent, readings across the grain may occasionally be as much as 2 percent lower in moisture content than readings parallel to grain.

Two percent isn't enough to be a big deal for woodburning purposes, especially since that's a worst-case scenario that only happens when the wood is wetter than it ought to be for burning anyhow. Orienting them with the grain is more accurate, but it's effectively an academic distinction.
 
Measuring with the grain is the preferred method for testing firewood. A MM works similar to an ohmmeter, except the reading is displayed in percentage of MC, rather than internal resistance.

My understanding is, a measurement across grain takes several growth rings into the reading which may be inaccurate for fuelwood. Some rings will contain more moisture than others.

Thoughts?
 
"In the same grain" is usually somewhere in the manual. I have done both and notice very little change.
 
For the purpose of firewood it doesn't matter.
 
Measuring with the grain is the preferred method for testing firewood. A MM works similar to an ohmmeter, except the reading is displayed in percentage of MC, rather than internal resistance.

My understanding is, a measurement across grain takes several growth rings into the reading which may be inaccurate for fuelwood. Some rings will contain more moisture than others.

Thoughts?

Inaccurate for fuelwood? How accurate do you think it needs to be? We're not burning just one growth ring we're burning the entire split. ;)

I think many times a MM doesn't tell the story the way it matters to us. With a MM it seems everyone looks for the highest reading at a single point of the split which is typically the middle. The number that matters to the stove is the moisture content of the entire split.
 
Even though I own a moisture meter and use it from time to time, you know what I'm gonna' say: "The best device for measuring the moisture content of split firewood is a multi-year calendar!";lol
 
I do both, and never noticed a difference
After going out and trying it both ways, I realized it only takes a couple of seconds to do both and haven't seen much if any difference - and to avoid confusion, I am talking about the moistire meter here : - )
 
Inaccurate for fuelwood? How accurate do you think it needs to be? We're not burning just one growth ring we're burning the entire split. ;)

I think many times a MM doesn't tell the story the way it matters to us. With a MM it seems everyone looks for the highest reading at a single point of the split which is typically the middle. The number that matters to the stove is the moisture content of the entire split.
Agreed, a scientific analysis of MC is overkill for firewood purposes. I should've mentioned earlier that I haven't used my MM in a couple years now... haven't needed it. This year's wood has been CS&S for two years, it's well cured.

A MM is probably better suited for selling firewood - and inspecting delivered wood - than for determining if my own stuff is ready for the stove. :)
 
A MM is probably better suited for selling firewood - and inspecting delivered wood - than for determining if my own stuff is ready for the stove. :)

Don't get me wrong I think it's a valuable tool if you're just starting out or purchasing firewood. I know it was a nice tool for me to have in my back pocket when I was starting out. It helped me figure out what was my "best" stuff to burn that first season when well seasoned wood didn't exist for me. After you get ahead it turns into more of a fun gadget or toy. :)
 
Even though I own a moisture meter and use it from time to time, you know what I'm gonna' say: "The best device for measuring the moisture content of split firewood is a multi-year calendar!";lol
Wise advice for those who plan to heat with wood for the long term, and have the room, but not really useful in the present. It's kind of like advising a down and out person, desperately looking for work to feed their family, that if they had a big bank account they wouldn't need to find a job so badly. Perfectly true, but does nothing to help them now.

We cut and process all our firewood, and we heat our house primarily (99%) with wood. We have never been 3 years, or even two years, ahead with my wood pile, and probably never will be (We just don't have the room), yet we always burn wood that is <20% moisture content. A moisture meter has been one of our key tools in managing this.

As to the original question, I've never noticed any signification difference measuring with the grain or across the grain, much more important to getting an accurate reading is to make sure you split (or cut) the wood and measure the freshly exposed split (or cut).
 
Last edited:
  • Like
Reactions: Beer Belly
Ya need to have the wood warmed up as well, say 40 deg minimum, sub 32 deg will not give a proper reading. should be a temp range spec in the manual we never read. Reading will be off also depending on what it's calibration was done for may or may not be mentioned in the never read book.
 
  • Like
Reactions: Fred Wright
Wise advice for those who plan to heat with wood for the long term, and have the room, but not really useful in the present. It's kind of like advising a down and out person, desperately looking for work to feed their family, that if they had a big bank account they wouldn't need to find a job so badly. Perfectly true, but does nothing to help them now.

We cut all and process all own wood and it's all free, and we heat our house primarily (99%) with wood. We have never been 3 years, or even two years ahead with my wood pile, and probably never will be (We just don't have the room), yet we always burn wood that is <20% moisture content. A moisture meter has been one of our key tools in managing this.

As to the original question, I've never noticed any signification difference measuring with the grain or across the grain, much more important to getting an accurate reading is to make sure you split (or cut) the wood and measure the freshly exposed split (or cut).

Don't much matter 'bout the now. Cut an oak now and mark your calendar 'cuse it'll be 3 years before it will burn well, no matter how down and out you are. If you are forced to buy wood or you split smaller, for necessities sake, then's the time for a moisture meter. Never said moisture meters weren't useful. And the calendar saying? Well, it's just a "good humor" saying I've always used. I didn't come up with it to hurt feelings of make folks mad.
 
  • Like
Reactions: Fred Wright
I do on occasion like to use my MM on my 3 year seasoned wood, just to see the low number==c
Not much difference in the 4 year stack.
 
  • Like
Reactions: Ralphie Boy
Don't much matter 'bout the now. Cut an oak now and mark your calendar 'cuse it'll be 3 years before it will burn well, no matter how down and out you are. If you are forced to buy wood or you split smaller, for necessities sake, then's the time for a moisture meter. Never said moisture meters weren't useful. And the calendar saying? Well, it's just a "good humor" saying I've always used. I didn't come up with it to hurt feelings of make folks mad.
I don't think anybody is "mad" or has hurt feelings. And what you say about green oak is perfectly true, but that doesn't seem to stop a lot of people from trying to burn it before it's had a chance to dry properly, does it? Problem is most of the people who burn that green oak don't own a moisture meter and are not aware of what seasoned wood really is.
I have a saying too, I like to say "if every novice wood burner was given a moisture meter, and shown how to use it, there would be a lot less ignorance out there about what constitutes seasoned wood". If they all had moisture meters it wouldn't take long for them to figure out for themselves that if they want to burn oak they are going to have to split it and stack it and let it sit for a few years. Of course, there are other types of wood besides oak. ;)

The couple of percentage points difference between warm or cold wood, or different wood species that moisture meters may or not have really doesn't mater much if you are getting consistent reading of <20% or less. What really maters is when people try to burn wood that is >25% or 30% MC and they don't even know it because they have no tool for determining where their at.
 
I don't think anybody is "mad" or has hurt feelings. And what you say about green oak is perfectly true, but that doesn't seem to stop a lot of people from trying to burn it before it's had a chance to dry properly, does it? Problem is most of the people who burn that green oak don't own a moisture meter and are not aware of what seasoned wood really is.
I have a saying too, I like to say "if every novice wood burner was given a moisture meter, and shown how to use it, there would be a lot less ignorance out there about what constitutes seasoned wood". If they all had moisture meters it wouldn't take long for them to figure out for themselves that if they want to burn oak they are going to have to split it and stack it and let it sit for a few years. Of course, there are other types of wood besides oak. ;)

The couple of percentage points difference between warm or cold wood, or different wood species that moisture meters may or not have really doesn't mater much if you are getting consistent reading of <20% or less. What really maters is when people try to burn wood that is >25% or 30% MC and they don't even know it because they have no tool for determining where their at.

Oh yeah man, I hear you! I know folks that have been burning wood for 30 years that think my 3 year old wood is "too dry and will burn like paper." Same folks would never think of burning pine for fear of starting a firestorm and burning the whole neighborhood. I've been a teacher for almost 30 years and I do my best to educate people but the "old ways" die hard. Mostly now I just say: "It's your stove and wood, burn as you see fit." It's kind of like discussing politics and religion in the same conversation! It usually ends badly!
 
  • Like
Reactions: Lumber-Jack
"The best device for measuring the moisture content of split firewood is a multi-year calendar!"
It has not taken me long to learn that lesson. My MM tells me high teens to low 20's. My insert tells me "get to cuttin,' splitin' and stackin', Rookie."
 
Re-split and moved another 4' x 16' rack of of oak outside today. A lot of what I recently bought was split too big and it is still too wet. I am gradually uncovering the maple that I cut/split/stacked a year ago October. Even that comes in around 20 - 23% though. I guess I am stuck with what I have for this year and I am working on next years too.
 
Status
Not open for further replies.