Cristobal Cristo

For the same reason as people wanting green lawns in sun scorched arid areas, or build from flammables where fire is part of nature cycle, or want cows on green pastures in the dessert, etc. It's one culture quickly spreading to areas incompatible with this culture. It was always like that, but within short time local conditions affected the practices (building, growing, eating) and new quality was produced which could be called permacultural. The question is if this process (of permaculturization) is still going on or if globalization - even on national scale, completely suffocated it.

Mutton is a meat for arid regions - a must for arid South West and West where I can not produce (with substantial time investment and equipment) a meager 2 lbs of tomatoes or cucumbers, but can effortlessly (I only provide water) produce 500 lbs of top quality mutton/lamb in a year.
I love anything coming from sheep - young, old, all cuts, all organs. The best and most flavorful meat among popular meats. It needs recipes from the places that thrive on mutton - Greece, Middle East, northern Africa.

The fire will travel down but because descending gases evenly fill spaces, the energy may get de-intensified and impair combustion, but if a descending channel was narrow enough and shaped correctly it could work as combustion chamber. You have to experiment.

Interesting. A few observations.

1. Energy radiated towards an insulated firebox floor is not wasted - it's accumulated and will be radiated back towards the door, walls, and then to the room. Changing this flow will not produce anything extra.

2. Stoves with ceiling port are built by Kuznetsov. Making the port horizontally at the top side to force the secondary combustion to happen when gases are descending may not work. In both rocket, Kuznetsov and in other designs from 100 years ago, combustion chamber is on the ascending path. Ascending hot gases want to flow in one stream, descending fill all openings creating multiple streams - lowering heat density and thus impairing combustion.

You would need to build a prototype. I would focus on a proper port placement to see if it works at all.

Douglas Alpenstock wrote:There is a hazy social notion that "gluten is bad" across the board.

My theory is that most of these modern diseases (despite Coeliac being known in ancient times) and allergies are caused by junk food ingestion. People that I know and who have allergies eat pure junk and at the same time I know/knew nobody with allergies who eats normal home-made-from-scratch  foods. They mess the body to such extent that it perceives normal substance as a problem - especially if it's taken out of context and used in amount not normally existing in nature. Someone may counter this notion saying that not whole wheat flour is also out of balance (sugar in cane juice versus white sugar affects body differently), but at the same time whole grains may contain anti-nutrients. I was always consuming white wheat breads (or wheat/rye) made of 4 ingredients, not 40. They would be considered high-end artisan breads in US. And those rolls...

Mike,

One advice. Try to avoid regular wood for forms. I was using dried wood planks, that I planed and  made forms for clay/perlie bricks that I fire afterwards. After few hours the forms bowed badly from moisture before the bricks dried. Next time I will have to line them with something or use different material.

Replacing part of cement with some fine aggregate would be great, but it would have to be really fine - as I can not imagine that some home mixing would be able to "lift" sand particles. Small bubble can easily support cement powder (or flour in egg whites foam), but if we imagine replacing it with sand or for better picturing coarse sand - the weight of aggregate particles will exceed the holding capacity of a small bubble.
I think that silica mesh at least 150 or finer could work. Please try and share the results.
I use silica 325 for making custom glazes for my ceramics. It's powdery like cement but also 4 times more expensive.
How much do you pay for 50 kg of grey cement?

I did not have a proper bread oven. Then I realized that flours in the store will not make a bread I want, so finally I have purchased King Arthur Lancelot Hi-Gluten Flour. I usually never buy food online, but it was totally worth. Finally my baguettes taste like bread to me. Also made the best pizza dough. I only like yeast leavened wheat and wheat/rye breads. No whole grain nor sourdough for me.

On domegaia website, mixer and foam generator can be purchased for $900. Let's add a $300 compressor.
The video of soap/gum/cement mixing produced a 8x8x16 (actually lower than 8") block at $9.3 with foaming factor of 1.5. After 170 blocks it breaks even and the tools are "paid". 170 blocks would build 19x8' wall. Soap/gum blocks would be hardly insulative and very non permie, because a lot of cement and chemicals would be wasted. It's presented as a cheap method... to produce very expensive and hardly insulating blocks, because in AAC at least 400% volume increase is the objective, not 50%. Using domegaia tools an 8x8x16 block would cost ca. $2 in materials, but could go lower if cheaper cement was sourced. Regular concrete block currently cost $3 in many locations and $3.5 where I live.

Within a footprint of 88x80 cm you could fit a fi 120 mm batchbox or shorty core. The bell could be 80x80x150 cm. The firebox door would face either the living room or the bathroom - depending where you want to feel more instant heat through the door. In theory a sidewinder could be fit into a narrower profile (and taller bell or same height bell and the bench), but smaller sidewinders may not work as well as normal design, but at 120 mm it would be worth trying.
Where do you plan to put a chimney?

After edit:
I have realized that on of the circles is the flue. I you built the 80x80 cm bell, you could extend it to the left in the living room - by adding 40x40 cm bell protrusion for the chimney hidden in the bell. It would look great.

My first oven was made of cob dome that I formed over a pile sand covered eith plastic bag. Around  10 cm thick, no insulation and non insulated floor that was sucking all heat. The opening for fuel was also the chimney. It was quite miserable and very difficult to bake anything.

My second one was a flattened batch rocket firebox - fi 200 mm equivalent, made of dry stacked red bricks. No insulation, but we managed to bake some inferior breads and sometimes good pizza.

Based on that firebox I built a real dual chamber oven, with firebricks, a lot of insulation and real cast iron doors. It burns super clean. I love it, but would make one improvement - complete insulation between the firebox and upper chamber, so after the burn, the upper bricks would not suck firebox heat. We bake a lot of breads, rolls, pizzas, make stews and smoke. Pleasure to use. It keeps heat for two days, so it can be quickly reheated to baking temperature.

You said that you are counting on having the oven floor to be heated by firebox ceiling. My measurments consider it to be inefficient. When the brick outside is 70 C - hot to touch, the interior is 400 C, so to heat the floor sufficiently, the ceiling will have to be heated to red hot temperatures and it will quickly compromise rather thermally delicate cob. That's why I always recommend traditional approach, used in all bakery and pizza ovens: firebox is the oven. This way you will always develop sufficient temperature without wasting fuel and the oven walls. With insulation all around and chimney damper it will always work. Around 40% of wood burning energy is emitted through radiation from flame and coals. When we add conduction of coals and convection heating of the firebox it will turn out that at least half of energy is in the firebox. The rest is heating the fues, other chambers, chimney and air.

If I wanted to build an oven as separate chamber I would build the firebox from insulating firebricks to direct as much heat as possible to the separate oven. I would also make the ceiling from metal (would need to be some quality heat resistant alloy to survive). I would also pad the door with insulating material to prevent the losses due to radiaton towards the door.