But First, a Movie!

Before we start on our adventure, let’s watch one, a movie made by the BBC about El Dorado,  the Lost City of Gold in the Amazon.

Sit back and watch the show in full-screen by clicking the small box on the extreme right side at the bottom of the player.

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Terra Preta Today


Significant current research on Terra Preta is conducted at Cornell University by a team headed by Dr. Johannes Lehmann.



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It Wasn’t All Preta…

In 2009, at a workshop on biochar at the Pony Farm in Temple, NH,  Hugh McLaughlin gave some history and ideas about the actual formation of the Black Earth.  First, most of it was not black.  There was Terra Mulata, brown earth.

Hugh refers to the book, 1491 – New Revelations of the Americas Before Columbus, by Charles C. Mann. It is worth the read!

Dr. Hugh McLaughlin

Hugh McLaughlin, PhD, PE has a professional consulting practice in Chemical Engineering. He is an expert on the properties and production of chars, created by pyrolyzing biomass, and the subsequent conversion to activated carbons.

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Charcoal in American History

The Tri-State area where New York, Massachusetts, and Connecticut border each other was the home of military ironworks for the Revolution, the Civil War, etc. The forests were stripped of trees for charcoal needed to produce iron. Quite a few iron furnaces have been reconstructed, but of the charcoal kilns these are the only ones I know of, reconstructed and left in nature in the hopes that they will be respected.  In fact, I have mixed feelings about putting them up on the Internet and, as you might have noticed, I have been cagey about where they are located.

Charcoal Kilns, Dutchess County, New York
This how they are sited, only a few feet separating them.  I have no idea how many there were in this particular spot.

For scale
Showing the scale and also the retaining wall behind the kilns.  They were built into an incline so that fresh wood could be loaded into the top from wagons.

From the rear, showing where the wood was loaded on the hill.

Front Detail
Here is the detail for the lower entrance. I wonder if the more even, rectangular rock is phyllite, found in this area and used since colonial days for fireplace hearths because it was thought to hold up very well to fire. It would make sense and phyllite does resemble this rock, but I am not a geologist!

Inside, showing the loading area and, above it, a circular vent. I assume that the vent was closed off once the fires got working.

Other vent holes can be seen part way up.

About one meter from the ground are some regularly-spaced rectangular holes that might have supported some iron beams to hold the biomass above the fires.

Around the kilns are these chunks of glass from the ash.

Charcoal Pits in the Northeast

Scattered through the woods in the Northeast are remains of other methods where charcoal was more commonly made during the colonial era.

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Farm Scale

Making Biochar for Farmers

If we are going to reduce the amount of carbon dioxide in the atmosphere in order to stop the greenhouse gas effect, we must do more than conserve energy and use sustainable fuel sources.  We have to actually remove carbon dioxide from the atmosphere.  Nature already does this.  It pulls carbon dioxide out of the atmosphere through photosynthesis and stores carbon in plant matter.  But when we burn it or let it compost or rot, the carbon is joined with oxygen again and goes back into the atmosphere as carbon dioxide.  The problem gas.

To break the cycle, we can actually keep the carbon in the soil by making biochar, charcoal.

It’s something that farmers can do to help themselves by improving their soil.  And help the rest of the planet!

If biochar is going to be used by farmers it has to be able to be made by farmers:  it not only has to be relatively convenient for them to put into their fields but also into their already busy workloads.  And it has to be in a quantity that can be applied to acres of farmland.  It has to be made by the ton!

First, meet Dirk-Jan Rosse, who has been experimenting with making biochar in place.

Dirk-Jan Rosse lives in farming country although he calls himself a “digger”, running an excavating company.  Since childhood he has prowled all over the woods and fields of northern Dutchess County, NY, where he still runs across traces of charcoal-making from the days when it was used to smelt the iron for weapons in the Revolution and Civil War.

Dirk-Jan has a lot of surplus wood on his own property.  He milled some lumber for his own use, but there was an awful lot more than he needed for himself and there was not much of a local market for firewood.

He has been thinking about how to make charcoal at a scale that would suit a farm using equipment available to a farmer. But being in the excavation business, however, he had his own commercial earth-moving gear that you would not really find lying around a farm.  This allowed him to ramp up the scale and the speed of making some tests, but on a smaller and slightly slower scale everything could also be done by tractor with a bucket and grapple.

He remembered those remains of charcoal pits and kilns.

His plan is quite simple: rather than make biochar someplace and then cart it to the field, why not actually make it in the field itself?  It would be based on a traditional way: covering a pile of scrap wood, tree clippings, cut-offs, etc. with dirt and letting it pyrolyze right on the spot.  The same dirt that forms the “retort” would end up as the home for the charcoal.

There is no apparatus required.  Just the existing dirt and some bad hay (of which there is plenty where we live).

What needed to be tested was the design of the pile, how the wood should be stacked, and what kind of air or smoke openings should be placed.


Again, the Bobcat can be replaced by a tractor’s bucket loader and grapple.

It’s time to light up!

After a few days of smoldering, the pile was ready to be opened.  Well, in truth, we were dying of curiosity!

For this much charcoal we need a REAL shovel…

This is only a small fraction of the pile.  There is plenty of good carbon to be put into the soil that has been taken out of the air.

The experiment is not over.  There will be more piles to make biochar and to improve the process: the smoke needs to be burned off, the air-flow improved…  the charcoal will need to be matched with appropriate compost…

The moral of the story:


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A Biochar Corn Harvest

A fallow field, one half remained fallow and the other half tilled in with biochar. And then we left the field untouched for 2 years. We did not add any fertilizer or pest control. Just left it alone. We ran the disc harrow over the land and planted some sweet corn on the whole field.

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Harvesting Goldenrod

Goldenrod is harvested with the same equipment as hay — a cutter, a rake, and then a baler.  For those who are unfamiliar with this equipment, the following is a short course in Farming 101.

First, the plants must be cut.

A few days later Dirk-Jan and I were in a far corner of the same field and we discovered some monster Goldenrod.

The cut golden rod still has some flowers and leaves which are not needed for pellets.

Golden Rod in Field

The plants are allowed to stay in the field for a couple of weeks so most of everything other than the stalk comes off in the process of retting,  (yes, similar to what it sounds like, rotting).  This allows the soft and nutritious material to return to the earth.

Retted golden rod

This leaves the stalks lying loose all over the field.  Not at all efficient for the baler to pick up.

Messy field

It now calls for raking.

The baler straddles the windrows and picks up the stalks.  This baler is called a round baler for obvious reasons.  You might have seen square (actually rectangular) bales which are quite different.

If the weather has been dry enough, the rake and the baler can run at the same time.  It’s a coordinated “dance”

The finished product, waiting to be picked up and taken to the pellet mill.

Finished Bale

Each one of these bales has the equivalent amount of energy as 40 gallons of oil when made into pellets for heating.  That’s money that stays here, not only in the States, but in the county!  It is carbon neutral; it does not pump carbon dioxide into the atmosphere from fossil fuels. It is renewable and we can look forward to a new crop every year.

Now it’s off to the pellet mill!

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The Pellet Mill

The bales of goldenrod stalks were taken a few miles away to Dirk-Jan’s pellet mill. The bales are put into a huge grinder and then into a hammer mill to become a powder which, in turn, is fed into the mill.

The mill compresses the fine powder under very high pressure and heat and forms the pellets.

The heat of the mill produces the steam seen in the film.
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The New Coal? Grass Pellets

Heat with grass not gas!

Let’s visit a plant nursery in Pawling, New York, that has been using grass — made into pellets — to heat their large greenhouses. The pellets are burned in an unmodified rice-coal stove.  For the sake of a video demo, we fired up the stove for the first time since it was used last winter.

Dr. Tom Reed and Dirk-Jan Rosse chat about making grass pellets for  heating.  Could this really be the new coal?

There is a lot of fallow farm land in our area — abandoned farms, land that has to be brush hogged for absentee owners, whatever.  Yet left as “weeds” one to two acres can heat a house for a year when made into pellets!

A couple of days later we walked the field and Dirk-Jan noticed some particularly tall goldenrod.  I have heard it said by some farmers that there is more money to be made from goldenrod than from corn!  It could be.  Harvesting goldenrod is a simple three step operation:  cutting, windrowing and baling.  No special equipment, no spraying, no fertilizer.  Much less fuel and time is spent on this crop.

This is not a demonstration project, proof of concept, or experiment.  No public or foundation funds have been awarded this project (or, for that matter, this website).  It is the beginning of a new business, bootstrapping and paying for itself as it catches on.

Continue here to see how this field of golden rod is harvested.

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The Biochar Workshop at Pony Farm

This is an introduction to the Biochar Roundtable at the Lodge at Pony Farm in Temple, New Hampshire, on May 9, 2009. It was a pioneering event!

Before we move on. let’s watch Hugh McLaughlin demonstrate some TLUD stoves he makes with scrap tin cans…

If you want a more graphic illustration of how the TLUD does not burn the fuel but rather the gases that have been driven off the fuel as smoke, here is a video I made showing lots of smoke being burned off. The next demonstration produced charcoal with a retort made from a recycled Cornelius keg.  I’ve taken the liberty of assuming that most people looking at this site would not be familiar with the Cornelius keg. In the following video, Hugh explains what it is and how to convert one as an excellent and affordable retort.

These kegs have been discovered by the homebrew beer set and they might be driving the price up.

And now for the keg in action as a retort for making charcoal from wood scraps.

You will see more videos of the Cornelius keg because Hugh gave me one to experiment with.  I can hardly wait!  This more fun than the old Gilberts Chemistry Sets  (if anyone remembers!).

Dr. Thomas B. Reed is going to show us his technique for making charcoal with inspiration from Jack Daniels.



Tom modified the Jack Daniels “rick” for a technique for making a home brew. Of charcoal, of course!

Dr. Hugh McLaughlin

Hugh McLaughlin, PhD, PE has a professional consulting practice in Chemical Engineering. He is an expert on the properties and production of chars, created by pyrolyzing biomass, and the subsequent conversion to activated carbons.

The Inventions and Works of Dr. Thomas Reed

“Tom Reed is a chemist and an inventor with more than a dozen patents, an author, and an expert in many areas of renewable energy.”

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Burning Smoke: Gasification


Let’s play with fire — and learn from it!

Gasification is central to understanding the efforts to produce smokeless and safe stoves for cooking with biomass fuels as well as making biochar. In layman’s terms, it means using heat to drive off the components of biomass that are not carbon and heating them in an air rich environment so that they burn and leave the carbon behind. So you are literally burning smoke and generating lots of heat. A primary supply of heat to drive out the volatile materials of the wood as smoke and a secondary supply to ignite the smoke.

Dirk-Jan built a gasifier to evaluate the grass pellets he produces and to assess how much slag and ash they produce.  It was kludged together with scrap parts he had lying around his shop and is certainly not a production model but it does illustrate how to burn smoke.


We have been taught to light fires from the bottom of the wood pile but in this video the fuel was lit by from the top while the hot air came from below. This gives the stove the name Top Lit Up Draft, TLUD.

When the fuel is lit from below it completely burns the fuel above it rather than just creating smoke. That leaves ash instead of the carbon in the form of charcoal, the desirable biochar. Pronounced “B-LUD”. The fuel is ignited from the bottom and up until a certain point generates a lot of smoke.

The TLUD has the advantage of producing biochar while it is being used as a cooking stove. TLUD has the advantage of producing biochar while it is being used as a cooking stove.

Here is a diagram to help with the terminology of the TLUD.

As I wanted to make a video that would illustrate how gasification actually burns “smoke” in order to produce heat, we ignited the fuel through a port at the bottom of the stove to generate lots of smoke and then lots of heat. If we had lit the fuel from the top, it would have been smokeless. This same stove works in two different ways: as a TLUD and as a BLUD. Pronounced “T-LUD”. The fuel is ignited from the top and is essentially smokeless.

A diagram by Paul Anderson of the TLUD gasifier stove.

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Hugh McLaughlin’s Stoves

The next demonstration produced charcoal with a retort made from a recycled Cornelius keg.  I’ve taken the liberty of assuming that most people looking at this site would not be familiar with the Cornelius keg unless, of course you are part of the home brew beer fraternity. In the following video, Hugh explains what it is and how to convert one as an excellent and affordable retort.

Now let’s see it in action!

There will be more video about the Cornelius keg because Hugh gave me one to experiment with and I can hardly wait!

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The Stovers

“More than half of the world’s population—three billion people—cook their food and heat their homes by burning coal and biomass, including wood, dung, and crop residues, in open fires or rudimentary stoves. Indoor burning of solid fuels releases dangerous particulate matter, carbon monoxide, and other toxic pollutants, and releases greenhouse gases into the air. The resulting indoor air pollution levels are 20 to 100 times greater than the World Health Organization’s (WHO) air quality guidelines allow. Unfortunately, the health risks and threats to the environment are on the rise: the International Energy Agency estimates that 200 million more people will use these fuels by 2030.

“WHO estimates that 1.5 million people die prematurely each year from exposure to indoor smoke from burning solid fuels. In fact, indoor air pollution from household energy is ranked fourth in the list of serious threats to health in less developing countries, after malnutrition, unsafe sex, and unsafe water. Women and children face the greatest risks. Breathing unsafe levels of smoke indoors more than doubles a child’s risk of serious respiratory infection and is associated with pregnancy problems, such as stillbirth and low-weight babies.” Partnership for Clean Indoor Air

I call them “Stovers”, a loose network of people who are experimenting on smokeless stoves that use very little fuel and ideally produce charcoal for use as biochar or for other heating.

A prominent pioneer in this field is Nat Mulcalhy of WorldStove.  His explanation and demonstration of this great stove is far better than the video, but please bear with it… and don’t worry, there are english subtitles!

I would love to get my hands on one of his Lucia stoves. I just happen to think this would be a great catalyst to trigger conversations that I could video.

Here is a combination of grass-roots organization and appropriate technology which contributes to the local economy.

In this next example, solar stoves at a refugee camp for Darfur refugees.

We can see how the stoves are made in the local community.

There are many other examples of economic development and stove technology coming on this website. But they all adhere to the belief that we must cut down on the amount of fuels we use for cooking and heating.

Bear in mind:

Nationwide, the estimated 60 million barbecues held on the Fourth of July alone consume enough energy—in the form of charcoal, lighter fluid, gas, and electricity—to power 20,000 households for a year. That one day of fun, food, and celebration, says Tristram West, a research scientist with the U.S. Department of Energy, burns the equivalent of 2,300 acres of forest and releases 225,000 metric tons of carbon dioxide. It also produces other air pollutants — including a few that might surprise you. Sierra Club

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Low-Hanging Fruit

Low-Hanging Fruit: easy steps, things we can do that will produce some results easily and quickly.

For example, spreading an inch or two of biochar on all the arable land on Earth in order to reverse and reduce global warming is not low-hanging fruit.  We might have to do it  to save ourselves one day, but it is not easy and quick!

But producing efficient, smokeless stoves to remove soot from the air is.

Using CF and LED light bulbs to reduce energy consumption, is.

Make your own list.  And then start picking your fruit!

Everything You Know About Composting is Wrong: Mike McGrath

Believe it or not, an entertaining talk on how composting our household garbage and raking up our leaves is all wrong.

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