Moisture content vs burn time video!

[ChadMc]

I watch this guys channel and this video he just posted was really cool. He really analyzes each burn. Now, we all know that the green burn is going to smoke like crazy and create creosote in that first stage of the burn but very interesting data at the end. Watch and tell me what you think!

 

[bigealta]

Good test. I'm surprised that the green wood did not have a longer burn time than the others.

 

[begreen]

Informative, but a 0% reading on the kiln-dried wood is highly suspect. Wood will absorb and equalize with atmospheric moisture. Even super dry flooring or cabinetry wood is around 8%.

Though he made light of it, the seasoned wood appeared to have the longest burn time by 50 minutes. Look at the graph at 13:10. The yellow line is notably longer.

 

[joefrompa]

The results of that test are highly suspect on green vs. seasoned wood. His trendline indicates they produced amount identical amounts of net heat over the course of ~4 hours and that the green wood had a lower peak but a longer "hump" of heat.

The theory would then be that (I don't know the total weight of wood) but that an extra 3/4 gallon of water across 30 pounds of wood thrown into the firebox yields the same total amount of heat output over the same period of time.

Huh? That water is absorbing massive amounts of heat in order to convert it to steam. That would explain it's lower peak, but it wouldn't explain why the seasoned wood drops BELOW the green wood in temperature subsequently.

 

[ChadMc]

The other thing he didn’t show was how the air was set on each burn. I can imagine the green wood had to be burned wide open for a while to keep it burning.

 

[NoGoodAtScreenNames]

That’s a huge coal bed he’s loading on too. With the same stove and my 33’ chimney I would melt my liner doing that. Apparently it works for him. But I bet the green wood curve would look much different starting fresh or with less coals. The coals are really going to bring down the average moisture content of the load helping it perform closer to the dryer wood.

 

[Ctwoodtick]

If nothing else, this video shows how dry wood leads to much cleaner operation.

 

[Caw]

That’s a huge coal bed he’s loading on too. With the same stove and my 33’ chimney I would melt my liner doing that. Apparently it works for him. But I bet the green wood curve would look much different starting fresh or with less coals. The coals are really going to bring down the average moisture content of the load helping it perform closer to the dryer wood.

Yeah I agree with this. My stove would go thermonuclear if I reloaded dry wood on that big of a coal bed not raked forward.

He mentioned that it took *30 minutes* for the green wood to ignite. Yikes. Imagine if it was a normal coal bed raked forward? Creosote city if it ignites at all.

Cool video but I'd like to see it again with a more normal loading scenario. We'll, more normal to me anyways. I think as said above you'd see a much bigger difference with green/seasoned wood.

I also usually measure my wood with the pins parallel to the grain not perpendicular. Less resistance so I think it's a more accurate number.

 

[ChadMc]

Yeah I agree with this. My stove would go thermonuclear if I reloaded dry wood on that big of a coal bed not raked forward.

He mentioned that it took *30 minutes* for the green wood to ignite. Yikes. Imagine if it was a normal coal bed raked forward? Creosote city if it ignites at all.

Cool video but I'd like to see it again with a more normal loading scenario. We'll, more normal to me anyways. I think as said above you'd see a much bigger difference with green/seasoned wood.

I also usually measure my wood with the pins parallel to the grain not perpendicular. Less resistance so I think it's a more accurate number.

That was my first thought. No wonder he got the green wood to take off. The fire box was probably 500deg when he put it in!

 

[moresnow]

Sooooo. Dry firewood produces the most heat.... Ooooook.

 

[stoveliker]

I think people like this run the risk to get people to do things in incorrect ways, leading to risks.

Measuring mc in the wrong way, loading on a half full firebox, etc.
And his data don't make sense to me. Other than the conclusion from @moresnow there is nothing reliable that can be learned here. One might say that well, we learned that wood should not be too wet - but showing measurements that give erroneous outcomes is likely to lead to more problems than it prevents...

 

[MR. GLO]

Yep the kiln dry guys pork ya. I know the feeling.. They dont want to leave it in the kiln for several days and mix it....

 

[stoveliker]

Informative, but a 0% reading on the kiln-dried wood is highly suspect. Wood will absorb and equalize with atmospheric moisture. Even super dry flooring or cabinetry wood is around 8%.

Though he made light of it, the seasoned wood appeared to have the longest burn time by 50 minutes. Look at the graph at 13:10. The yellow line is notably longer.

Doesn't that just mean he measured longer? The curves superimpose, so if he hadn't stopped for the other two loads, they'd likely have followed the same path for 50 more minutes...?

 

[MR. GLO]

Doesn't that just mean he measured longer? The curves superimpose, so if he hadn't stopped for the other two loads, they'd likely have followed the same path for 50 more minutes...?

His gauge might not go to zero or read low. Assuming it was 4.5 or so...

 

[begreen]

Doesn't that just mean he measured longer? The curves superimpose, so if he hadn't stopped for the other two loads, they'd likely have followed the same path for 50 more minutes...?

Maybe. The test is not exactly scientific. Lots of data missing, like the starting stove temp, depth of coal bed, etc. A top-down cold start might have been more descriptive.

 

[Caw]

A top-down cold start might have been more descriptive.

The curve for the green wood could just be a tiny peak then straight line cause there's no way he's lighting 38% green cherry top down with a little kindling!

I burned a lot of 25% ash this season by mixing in a couple logs here and there with the good stuff. Thats the easiest way to use under seasoned wood. The few loads I experimented on with it as the sole fuel were brutal. Long relights, tons of coals, never could close the air beyond 1/3 open, stove never got hotter than 500-550 when I usually cruise at 600-650.

 

[stovelark]

I think from the video he just proved the Enviro Boston burns beautifully no matter what you put into it- heehee.
It is a forgiving (like all of the PNW designed stoves) burn engine. Not knocking our cast and soapstone friends, but a steel stove is easier and more forgiving to run. That insert sure seemed hot too, wondering if his pants was warm behind him... Interesting, but its still the same good dry seasoned wood- happy stove, happy stove owner.

 

[gthomas785]

I think you guys are being a little harsh. Looking at the area under each curve represents the total heat generated from each load, and there's a huge difference between the green wood and both seasoned and kiln dried. His graph doesn't demonstrate that super well but by eye I would estimate at least 30% less heat produced by the green wood. Most of the difference is right at the beginning so it's not too surprising that he gets the same burn time. Heck, I get about the same burn time in my stove with poorly seasoned wood because it takes forever to light off. What this experiment doesn't account for is how long one might wait before reloading not just based on stovetop temps, but due to the extra heat released in the initial part of the burn making the space warmer and not needing to reload as early.

Yeah, he used the moisture meter sideways. That was pretty bad. But overall I thought this was a really informative experiment and definitely more hard data than I've ever taken the time to collect on this subject.

 

[ChadMc]

I think you guys are being a little harsh. Looking at the area under each curve represents the total heat generated from each load, and there's a huge difference between the green wood and both seasoned and kiln dried. His graph doesn't demonstrate that super well but by eye I would estimate at least 30% less heat produced by the green wood. Most of the difference is right at the beginning so it's not too surprising that he gets the same burn time. Heck, I get about the same burn time in my stove with poorly seasoned wood because it takes forever to light off. What this experiment doesn't account for is how long one might wait before reloading not just based on stovetop temps, but due to the extra heat released in the initial part of the burn making the space warmer and not needing to reload as early.

Yeah, he used the moisture meter sideways. That was pretty bad. But overall I thought this was a really informative experiment and definitely more hard data then I've ever taken the time to collect on this subject.

Ha I was going say you guys are being harsh. I would also say that I have reloaded on a coal bed like that before on a brutal cold day. All the times on here people say “I have sub par wood, should I burn it or wait?” Well
Obviously waiting is better but in a pinch green wood does give of heat. An experiment on creosote build up would be interesting!

 

[stoveliker]

You can't use the area under the curve because that air settings (and hence the heat going up the flue) are different.

Too many uncertainties here. But my main criticism is that things are done here that may invite new folks to do the wrong thing all while thinking they are doing it right.
People may end up with a flue full of creosote because of this.

 

[gthomas785]

You can't use the area under the curve because that air settings (and hence the heat going up the flue) are different.

Too many uncertainties here. But my main criticism is that things are done here that may invite new folks to do the wrong thing all while thinking they are doing it right.
People may end up with a flue full of creosote because of this.

The area under the curve represents (stovetop temp) × (time) which is the closest estimate of heat output you're going to get. No, none of this accounts for the heat going up the flue, but that's irrelevant if you just want to know the heat output of the stove.

IMO there's very little wrong with how he burned the stove. Yes, he could have reloaded on less coals. Yes, he could have not burned green wood at all or emphasized why it shouldn't be done. and yes, he could nave used the moisture meter correctly. But criticizing the experiment for not being scientific is kinda mean IMO (coming from a scientist) seeing wood burning is really not all that controllable to begin with I think he did a pretty good job.

 

[stoveliker]

The area under the curve represents (stovetop temp) × (time) which is the closest estimate of heat output you're going to get. No, none of this accounts for the heat going up the flue, but that's irrelevant if you just want to know the heat output of the stove.

IMO there's very little wrong with how he burned the stove. Yes, he could have reloaded on less coals. Yes, he could have not burned green wood at all or emphasized why it shouldn't be done. and yes, he could nave used the moisture meter correctly. But criticizing the experiment for not being scientific is kinda mean IMO (coming from a scientist) seeing wood burning is really not all that controllable to begin with I think he did a pretty good job.

Fair enough. You said "total heat generated", I said that was incorrect. Moreover, one could optimize air settings for each burning characteristic. We always do. So these curves don't tell how much we would get in the home.

And the safety issue (making people believe that it's proper mc determination, while setting them on the wrong track) is my main criticism (from a scientist too... - but then again we are, or at least I am, rather opinionated..).

 

[gthomas785]

Ok, I mistyped the first time. I meant the total (useful) heat you get from the fire, which would not count what goes up the chimney.

 

[Caw]

I just wanted to chime in that I too am a scientist by profession .

Now that I am credentialed I think some of the criticism has been fair. People who are unfamiliar with moisture meters or how to properly reload/operate a stove will come across videos like these and take them as gospel because they don't know any better and the guy appears to know what he's doing. That's dangerous.

I personally just don't like seeing green wood loaded on coal mountain and using that as a way to compare. Sure you can always burn it in a pinch but we all know it would never ignite if tried under remotely normal reload conditions.

Also have to remember the audience here...we're a bunch of stove and wood nerds! Ofc we're gonna pick it apart lol.

Side note- 45 degrees out here at night in Feb. Wtf!

 

[gthomas785]

I just wanted to chime in that I too am a scientist by profession .

Now that I am credentialed I think some of the criticism has been fair. People who are unfamiliar with moisture meters or how to properly reload/operate a stove will come across videos like these and take them as gospel because they don't know any better and the guy appears to know what he's doing. That's dangerous.

I personally just don't like seeing green wood loaded on coal mountain and using that as a way to compare. Sure you can always burn it in a pinch but we all know it would never ignite if tried under remotely normal reload conditions.

Also have to remember the audience here...we're a bunch of stove and wood nerds! Ofc we're gonna pick it apart lol.

Side note- 45 degrees out here at night in Feb. Wtf!

Sure yes that's fair. Not the best example to be setting, also nowhere near the worst I've seen. I was responding more to the criticisms of the experiment and claims that his results were suspect. To me it's a fascinating and well conducted test with some really interesting results even if they weren't interpreted very well.

Re the reloading conditions, you need a lot of coals to get green wood to burn, so to me it makes sense to put all the loads on the same large coal bed for a fair comparison. Of course that's not how you'd operate the stove normally, but it's a strong attempt at a controlled experiment.