Forerunner Hatfield

Better chips = smaller and thinner, according to what I've read of Jean's experiences.
Smaller chips offer more over-all surface area for the methane producing microbes to feed upon, thus a more efficient use of the vegetable matter and perhaps quicker release of the gas.

paul wheaton wrote:
How high is that opening?

Just over five feet high. My tank was 5'6". We're not short people, but not giants either, so it works. My cellar ceiling is about seven feet.

As I said, three feet at best. It is a thin cover at the mouth of the tunnel.
It gets thicker toward the cellar itself.
I had hoped to dig it out by now and replace with concrete, then the price of scrap fell, and funds have become scarce. Now I'm debating whether to go with logs...

Paul, I don't know that my experiences are worthy of mention other than to say, don't use cottonwood for ANY underground construction, regardless of how well you might hope that you've waterproofed. I used old electric line poles for my frame, and the c-wood 2x4s for my sheeting, braced the roof with a "plus sign" cross made of oak, used a double layer of the c-wood for my roof, wrapped the whole affair in lots of plastic, backfilled with pea gravel, covered with dirt in the form of a mound, plasticked AGAIN, over that mound and well beyond the outer perimeter of the entire structure, then covered all with more dirt-- probably three feet deep at best.
It kept taters and carrots cold but unfrozen and homemade cheeses that we kept inside a little refrigerator were maintained at the right temperature range to cure well into June. All in all we were happy with it, until we noticed that the c-wood was rotting pretty badly in spots. ops:

I'm glad that Oehler had the foresight to warn others about species type.

The only pics I could scratch up were of the steel entrance and a portion of my wine collection behind which you can see the pole construction and the painted 2x4 sheeting. Between the steel entrance and the main cellar I set a round steel tank for a tunnel to get us further back in the earth.

My understanding is that there are two somewhat corrosive substances found in raw methane. One can be removed by passing the gas over iron oxide, i.e. rusty steel shavings; the other is removed by bubbling the gas through lime water. This begs the question, "what sort of lime" ?

I, too, am an avid Jean Pain fan from back when I first stumbled across the Mother Earth article referencing his work. I've been composting on an industrial scale ever since, having applied twelve inches or more of the finished material to, roughly, twelve acres of ground. I have yet to see the productivity and benefit of heavily composting soil max out. Taste, size, disease resistance, keeping quality, drought resistance and plant appearance continue to improve every year.

The only other portion of Jean's technology that I've yet to apply is compost heat.
I poured three large concrete bays against the east wall of my home several years ago and use those bays to construct and maintain three compost heaps. Two are always aging. One is always under construction. I heat the house exclusively with a wood stove of my own construction, and noticed a considerable difference in the amount of wood required to heat the home the first year the compost bin assembly was in place. Ambient temperature in the home was increased by approximately ten degrees that particularly cold December.
I built the center bay a bit larger than the outer two with the hope of eventually placing a large stainless tank over it to collect rain water, and subsequently heat that water as it passed through copper coils imbedded in the compost below, to provide hot water for the home. My bins hold about twenty tons of compost material each. Situating the piles so close to the house has not been a problem.
We compost humanure right along with everything else, as described in Joseph Jenkins' "Humanure Handbook", and find that ALL unpleasantries are summarily eliminated through the use of a carbon cover. We use sawdust, straw, leaves or wood chips to accomplish that end. Having the pile right outside the kjitchen window also saves multiple steps in disposing of kitchen waste. 

No luck on the tamarack....central Illinois here.
But, black locust we have in abundance.

Where is Sepp located ? I've not read enough about him yet to see mention of that.

I can shed some light on this.
I read the book by Mike Oehler and immediately set to work on a root cellar using that technology. Let me make my point clear as secondary perhaps only to drainage...... wood species, wood species, wood species.

Being a resourceful individual, and apparently having my better judgment clouded by hope and exuberance at the time, I used, for my "sheeting", a large pile of cottonwood two by fours that I had recently inherited from a local sawmill friend.
The structure did give me ten years of very dependable service before the natural and untimely deterioration of the cottonwood made it unsafe.

I have since used large steel storage tanks, buried horizontally, filled partially with pea gravel to make a level floor base on which to pour concrete, for my underground root cellars.
I expect to get multiple decades of service from these steel tanks, but would like to get back to more natural construction in my future projects.

Does Sepp indicate any species preference for his underground logs ?