earth oven building errors to avoid

Beginning an oven building adventure...click on the photo to read the builder's story...

Beginning an oven building adventure…click on the photo to read the builder’s story…

Especially when building a larger oven, there are some clear earth oven building errors to avoid. (Building an oven is simple, but the truth is that nothing is quite as simple as it may first appear, especially when you build a fire in it.) Heather Coiner of Hat Creek Farm in Virginia (in photo) has generously documented some of the mistakes they made on a commercial-scale oven they built (and used successfully) on their farm — and which they recently took down after building their next oven — a full-scale brick oven built by Eric Moshier, of Solid Rock Masonry. Here’s the link. It bears repeating that pre-testing material choices (especially insulation) can prevent some mistakes. However, increasing the scale of the oven also increases the intensity and duration of heat effects, which needs to be factored into the equation. If you can start small, accumulated experience will build up your intuitive knowledge of your materials, which will have a good effect on your decision-making…

“Go slow, pay attention, be careful…”

Thanks, Heather, and congratulations!

Earth Oven builders in Ecuador, Manuel (10), Juan Carlos (6)

manuel:juancarlosA builder in Alaska sent me this story about an earth oven she built in Ecuador, with two helpers. At the ages of 10 and 6, they are clearly competent. Margaret writes:

Winters in Kodiak were beginning to get to me.  I had it in mind to snow goose it away in a warmer climate for the coldest, darkest part of winter.  Alan and his girlfriend, Loretta were due to get married on their farm [in Ecuador].  They invited me to the wedding.  And so I went.

I had always said to Allan that if I did ever get to Ecuador then I would build them an oven.  What a fine wedding present that would be ……

The boys were on holiday from school and I guess curious as to what this strange white woman was doing scrabbling around the local countryside in search of flat sided rocks with which to build the platform for the oven.  Every day the family would join us and we’d pile into Alan’s little truck and go in search of the perfect rocks.

When it came time to start the actual build, Manuel and Juan Carlos became cherished members of the work force.  Every morning they would be waiting patiently either by the front door or the growing pile of rocks.  We marked out foundation and began to dig.  Then came mixing the mortar and choosing which rock would go where.  Manuel and Juan Carlos were by now so a part of the build that it was only natural that they would be participating at every stage.  We didn’t share the same language so everything was shown by example.  I showed how best to select the rocks and how to set them on top of each other being careful to span the join of the rocks they were covering.  The boys caught on very quickly.  Manuel and Juan Carlos working as a team, choosing very carefully which rock was going to go where, disregarding any they didn’t feel fitted ‘quite right’.  They soon learnt that the long, thin rocks that I had rejoiced so much when found were the ‘tie’ stones and they understood straight away the principal.

With the platform came the mess.  At the end of every session came clean up.  Both boys armed with wire brushes and scrubbers happily plugged away, still not realizing or conceptualizing quite what it was that we were building but getting into it just the same.

man:juanCThen came the oven itself.  The family were now thoroughly absorbed in the whole process so when the word got out that we needed clay and sand and granular finings, materials began to pour in.  Including some very, very much sort after red clay that came from one particular far off mountain.

And so the mixing began.

Friends and neighbors flocked.  It wasn’t long before everything in the near vicinity became coated, caked and splodged with the gooey red clay.

I helped the boys make the form which they patted until smooth and firm to the touch.  When it came to starting the actual oven itself, it was very obvious that the boys were desperately keen to stay in on the action.  Things there on in happened very naturally.  Manuel adopted the post of ‘ Head Oven Builder’ and Juan Carlos and myself as his chief apprentices and tenders.

man:juanC2I saw in both boys the blossoming pride and sense of achievement at the end of each stage of the build.  I saw their dedication and commitment to do their best at every turn and their willingness to see each stage through even though it sometimes got late and it was obvious that they were tired.

When it came time to carve out the door and dig out the cavity, Manuel automatically assumed the job and the responsibility be his and rightly so.  I stood back, silent, hardly daring to breath, nerves stretched to breaking point as I watched Manuel began to confidently scoop out the sand form.   I watched as without any word of instruction, Juan Carlos positioned himself with the squeaky, old, rusty, lopsided wheelbarrow to take away the sand that was coming out.

manuel2Between them, Manuel and Juan Carlos designed and built the rim around the oven door, Manuel making sure over and over that the door be a perfect fit, which it was…..

Oh, the boys were so proud when we lit the first small fire.  We kept it going off and on for a couple of days and then we fired it up proper.  And of course, it was Manuel with the help of his younger brother who fed it until it was a smokeless flaming blaze of molten orange and red.

The boys are older now.  But by all accounts still passionately proud and fond of their oven …… the oven that they built. They have reportedly assumed propiety rights to attending and baking in the oven!  And word is that both  boys have baking down to a fine art!

Wood-fired, earth-oven pizza grows a family business in Cedar City UT

Wood-fired, earth-oven pizza grows a family business in Cedar City UT

The Murray family needed extra income to pay dad’s college tuition; he had already made a little backyard oven, and decided he could make a bigger one on a cart and run an outdoor pizza business. My favorite line from the video (below) is Jason expressing amazed gratitude for his wife Cindy’s support: “How many wives would let you make some stupid oven in your backyard out of mud and then put it on a trailer and go out on the street, you know?” They were so successful tho, making pizzas outdoors in every kind of weather, that after several years, they’re now opening an indoor restaurant!

Here’s their facebook page

Their kickstarter campaign is already funded, but you can see it here.

And here’s an article with more of the story.

Way to go, Murrays! And kudos to Conrad Laga for the beautiful video, too…

Wood-fired earth ovens: experiments in DIY firebrick (aka “castable refractory”)

I’ve been experimenting with cheap ways to improve lo-cost wood-fired earthen ovens. How can I make mud denser, harder, and more durable? Without going to bricks and/or spending a lotta dough? Adding sand to mud reduces shrink and increases density. But clay and sand are generally still less dense (hold less heat) than a good, hi-fired dense firebrick. Hmmm…

mix exp.1

materials and lab: soapstone dust on left,
fine mason’s sand on right.

Experimental Goals:
1. to increase the density and toughness of a clay/sand thermal mix appropriate for building wood-fired ovens (and other wood-fired appliances?), 2. to fabricate a higher quality cast dome (“earth-oven”) style oven. Strategies: 1. adjust the mix of particle sizes to maximize density, and 2. amend/strengthen/improve the clay binder with sodium silicate (aka waterglass, a mineral solution which fuses at typical oven temps). Here’s three cups of packed sand, and a cup of packed dust. Three plus one equals 4, right? Wrong. Add the dust to the sand, mix it well, and you get three cups of mixed stuff.

I cup of soapstone plus three cups of sand equals...

I cup of soapstone plus three cups of sand equals…

mix exp.4

…three cups of “dusty sand”! The dust disappears into the gaps between sand particles…

mix exp.3

other cheap dust options might include crusher fines from a gravel pit/quarry, agricultural rock dust, mineral powders from a ceramic supplier, super-fine bagged sand, etc.

Each of these resulting three cups was about 15-19% heavier (and denser) than a cup of plain sand. (The dust is soapstone fines from an Oregon outfit that quarries and cuts its own stone; it’s extraordinarily fine, but other stone or brick dust — or super fine sand — will also work. Of course, if the particle size isn’t small enough, you’ll end up with greater volume — and more unfilled space. Engineers calculate surfaces and shapes and mix their aggregates accordingly.)

mix exp.6

I used my wife’s baking scales to measure weight, so take my figures with a grain of salty sourdough — or three…

OK, now I take my three cups of dense mix, and add a cup of wet clay. Three plus one equals four, right? Wrong again. Because clay particles are flat as well as fine, they will fill even smaller, tighter gaps between all those fine particles. And they’ll glue everything into a solid mass — like a dense, heavy brick. (Again, things will vary according to your clay, water content, and mixing, but in general, the increase in volume will be anywhere from negligible, to much less than the single unit of added material.)

Dust, sand, and clay would make a fine mix, but the shortcoming of a mix is just that — it’s a mix; different particles and different compounds behave differently. Over the long term, repeated heating and cooling can cause particles of a mix to separate and fall out — leaving you (or your customer) with bits of grit or sand in their pizza. Not what we want!

While it may be very noticeable in a clay-sand mix, the truth is that it can happen to the best firebrick as well, because outside surfaces get much hotter much faster than interior mass. As a result, surfaces can degrade and crumble — also called “spalling.”

To treat spalling oven surfaces, I often recommend a compound called sodium silicate, or waterglass, which binds everything together, even (especially) at high temps. Mix it with water (about half and half) and either spray or brush on. It soaks in quick and deep, and serves to “fix” a substantial layer of material.

Since sodium silicate is also used in the manufacture of hi-temp mortar, I’ve often wondered whether it would be worth adding to a regular clay-sand mix. So I made a clay:waterglass mix that was approximately 4 parts wet clay to 1 part waterglass. The clay had roughly the consistency of thick peanut butter or bean paste. After mixing, I packed the clay and dusty-sand mix into a brick form (leftovers were made into a ball).

mix tests2 (SIDE NOTE RE: WATER: the clay came out of the bottom of a bucket where it had been soaking for months. From previous experience, I figure it contained about a half gallon of water, so that means the liquid in the mix was roughly a 30% solution of waterglass. I was told by an industry rep that typical refractory mortar is made with a 40% solution, so I figure I’m in the ball park.)

RESULTS: both bricks appear to be roughly the same weight and density (and pretty close to firebrick densities!) But the really interesting result, so far, is shrinkage: the clay brick shrank a good quarter inch out of 7 inches total — almost 4%. In the photo, it’s the bottom brick, in the original mold it came out of. Above it is the waterglass brick, which had negligible shrink!

The surface hardness of both seemed relatively equal; both released grains of sand and grit when I abraded them (pretty hard!) with my thumb. Here, I think, compaction is very important, so all particles are in contact with each other, and you end up with a smooth, hard surface. This requires keeping the mix quite dry, and really whacking the material once the sand form is covered (I use a 2×4).

FOLLOWUP: ADDITIONAL BRICK TESTS:

Around here there are a lot of gravel roads made with local crushed rock. Most of it seems basaltic: black, dense, and heavy, usually about 3/4″ bits and smaller (called “3/4 minus”); it also has plenty of fines so it compacts into a smooth, hard surface. I’ve used it for various mixes, in particular for adding thermal mass to a big oven. After I did the tests above, I added some road base to the sand-and-soapstone-dust mix, in a 3:2 ratio. The resulting brick was even heavier than standard firebrick, and significantly harder than the mix of pure sand and soapstone dust. Given that “road rock” or crushed gravel is probably easier for most folks to come by, it might be just the thing for this purpose. Here’s some pix:

L to R: standard commercial hard firebrick, homemade brick of sand & soapstone dust, homemade brick of roadbase, sand, and dust.

L to R: standard commercial hard firebrick, homemade brick of sand & soapstone dust, homemade brick of roadbase, sand, and dust.

 

L to R: standard commercial hard firebrick, homemade brick of sand & soapstone dust, homemade brick of roadbase, sand, and dust.
IMG_9101

The pure sand and dust brick is a bit softer: you can see the dusty spots to the L of my thumb, where I rubbed off grains of sand.

IMG_9102

The brick made with road base came out harder; less stuff came loose when I rubbed it w/my thumb.

 

 

 

 

 

 

 

The downside of waterglass is that it’s somewhat caustic, so glove your hands when you work with it.

Waterglass runs about $10-$15/gallon — a pretty cheap addition to an already cheap materials list.

Closing Story: A teacher presents his class with a large glass jar full of golf balls. “Is it full?” he asks. “Of course,” the students reply. He tips in a bag of marbles, shaking the jar as he pours so they fill the spaces between the golf balls. “OK, now it’s full, right?” “Right!” say the students. Then he pours in dry sand, again, shaking lightly to fill the (smaller) spaces. “Now it’s REALLY full, right?” “RIGHT!” yell the students. “The jar is your life,” he says. “The golf balls are the important stuff: family, kids, health, community. The pebbles are pretty important — earning money, keeping your boss happy, keeping your car maintained and your house painted. The sand is the little stuff: email, TV, the newspaper. If you fill up the jar with pebbles and sand, you won’t have room for golf balls, but if you start with the important stuff, there’s always room for the little things.” Then he grabbed his coffee pot, and poured in the whole thing, and a container of milk. The liquid didn’t even come up to the top… “That,” he said, “is just to demonstrate that even when think your life is really REALLY full, there’s always room for coffee with a friend….”

Combining Earthen and Masonry Techniques in Wood-Fired Oven Construction

Is it made of earth or brick?  This is a common distinction in the world of wood-fired ovens and comes with a whole slew of assumptions.  “Earth ovens are cheaper, easier to build but less durable.”  “Brick ovens are expensive, harder to build but more professional and will last longer.”  The oven build documented below is an exploration of the combination of these techniques to leverage the advantages of each.  We use earth where its sculptural quality allows us to perfectly mold it to the shape that we desire.  We use brick where it will give a good durable surface for cooking and in the entrance way to withstand the abuse of heated and passionate cooking.  The book Build Your Own Earth Oven provides further reference for these techniques.

IMG_9175 IMG_9188IMG_9227 IMG_9231 IMG_9232base-webfloorarch-definition

Using rope to define the shape of the catenary vault.  The plywood is cut and the negative shape is used as a screed.

filling-in-hearth-webvault-screedIMG_9247IMG_9246IMG_9248IMG_9257 IMG_9259straw-clay-layer-familyIMG_9267IMG_9277

agrarian-ale-oven-plus-nateIMG_9304

 

Eventually, a whole outdoor kitchen and service bar was built around the oven!….

 

brad-fire-oven

Useful Links for Further Reading:

UK Earth Oven Project to help Bedouins


Here’s a new oven story that popped up one day via Google Alerts. It comes from the founder of The Makhad Trust, a UK non-profit focused on helping Bedouin tribal desert communities. It began with the planting of an acacia tree in the desert and continues, in part, by restoring the communal hearth — an earth oven. The back story, as published on their website, follows:

“Danny Shmulevitch, the founder, was walking along an ancient pilgrim route that runs through the Sinai Desert. He saw, sitting by the side of the path, a small girl wearing traditional Bedouin dress, who was hoping to sell cans of cola to passing tourists. She was, clearly, not happy.

“Politely refusing the offered can, he asked instead for a glass of tea, invoking the ancient tradition of hospitality to strangers. She took him to the family house, in a garden in the nearby desert oasis of Ein-Khudra (Green Spring), which was one of the stopping places of the Israelites in their journey through the Sinai wilderness. Gardens have been cultivated there by Bedouin families for over two thousand years, but four out of the five gardens had become derelict.

“In return for the hospitality, Danny made the little girl’s father a promise. He planted an acacia seedling in their garden and asked them to look after it carefully. When he came back, he said, if it was still growing he would bring help for Ein-Khudra.

“The family believed in this promise: the acacia tree (as it now is) was watered and nurtured and when Danny returned in May 1988 he brought a group of students and staff from Ruskin Mill College, an educational centre for young people in Gloucestershire, England, to help restore Ein Khudra.

“They built a shelter, a water cistern and a compost toilet and planted a small tree nursery. These were the needs identified by the Bedouin family as the first steps towards regenerating the oasis gardens. Working together, the Bedouin, students and staff created the first ‘makhad’—a meeting place in which to share hospitality.”

New Rocket Oven design by Flip and John

Jon and Flip Anderson have been working with Aprovecho Research Institute and building smokeless cookstoves in Haiti. They came up with this neat “rocket oven” design that answers some of the questions I get from folks about combining the dome oven design w/rocket technology. By simply using clay and organic matter and applying principles of mass and insulation they have created a beautiful, versatile, oven that can do significant baking w/very little fuel. For more about their work on developing business opportunities and helping with deforestation problems, goto www.RechoRoket.com. Here are a couple of their videos (they’re also working on a book!):

 

Bluegoat Restaurant Oven, w/insulation-in-a-basket

Here’s a little video showing the construction of a super-insulated restaurant oven. The “basket” design seems to be a pretty inexpensive and effective way to insulate — not necessary for every oven, but for ones that really get regular use, I think it’s worth it… It’s a pretty big oven, too, so I opted for hand-made mud bricks instead of mud over a sand-form. For more details about the technique (including brick-making, as well as photos of how well the insulation protects the bamboo), there’s an extensive post and pix about the Gathering Together Farm Oven, which was similarly (re)built.     — Kiko

 

Earth Oven variant: insulation in a basket over jumping bricks!

The earth oven at Gathering Together Farm's restaurant, Philomath, OR

Insulate! Insulate! Insulate! This oven gets used about 5 days a week, so it never cools down — partly thanks to 11″ of insulation under the hearth (vertical wine bottles in perlite), and about 8″ of loose perlite over the dome (poured into a basket made of bamboo covered in clay/plaster soaked burlap and mud). I built it for a local CSA farmstand restaurant (gathering together farm). The whole story (build and repair) follows, complete w/photos of making our own bricks and laying them up from the inside out!

The oven started in a public workshop; folks came to make mud and learn and we built the basic oven in a weekend.

I spent another week or so building a bamboo basket around the oven to contain loose perlite insulation. Loose perlite provides the best insulation value for the money, in my opinion. I then covered the basket frame with mud-soaked burlap and more mud plaster, and finished it to look like a big land-turtle shell.

a rough split bamboo basket is woven and tied over the oven, to be covered with cloth and mud, and filled w/loose perlite insulation

BUT! (and this was my fault for not watching more closely), the dome came out a little flat. Usually, when it’s not quite right, I tell folks, “OK, time to tear down and rebuild.” (Teacher tip: it’s a great way to conquer the fear of doing it wrong—)

And it’s the only way to prove to folks the truth of my favorite oven-building adage: “the second time is easier and faster.” But I let myself be convinced that the dome was adequately curved. It wasn’t. A year later, it was bulging downward, at the rate of about one eighth of an inch per month. Collapse was inevitable.

“Well,” you must be thinking, “didn’t you say the second time is easier and faster!”

Yes, well, OK, but…even had I been able to halve the time for building the oven and the large, sculpted shell containing the loose perlite insulation, I would have needed at least a week, not including the time required to dry out the damp oven itself. The restaurant uses the oven 5 days a week, and I didn’t want to be responsible for two weeks of down time—

nor did I want to put in that much (unpaid) time myself.

So the need for speed provided a perfect opportunity to try something I’d been wanting to try: making a brick dome using thin mud bricks laid on an angled bed of mortar, with successive courses in a series of shrinking circles to close in the dome—

without formwork! It’s traditional for ovens and vaulted or domed ceilings. I’d seen ceilings done this way in Mexico and wondered, “how did they do that!?” as well as photos of German mud-brick ovens made the same way.

It sure did make me appreciate bricks: pre-dried, pre-shrunk, easy to work with, and quick. Since they are relatively small, they shrink without cracking, which means you can use mud with a high percentage of clay. Clay holds up better to the thermal demands of an oven than a typically sandy cob mix, which relies on lots of sand to limit shrink. And if you’re working in a situation where time = money—that is, if you’re building an oven for someone else—you can make bricks at your leisure, and store them for when you need them. Mud has higher value when it’s made into a brick, so you can charge a unit price for each nicely squared blob of mud, but since bricks make for a quick build, you don’t have to spend so much time on the site building, drying out the oven, etc. (Here starts the slippery slope of professionalism, which is, as Collette said of writing, much like prostitution: first you do it for love; then you do it just for friends; then you do it for money. And then you set up guilds and unions, a licensing board with bonding and contract requirements with related insurance and legal industries, then lobbyists and trade agreements and complete control—

which spawns renegade activities like how-to books for home-bakers and oven builders, backyard mud ovens, internet groups, and here we are!)


note the cracking bulge at the top center of the oven ceiling. I cut a story stick that just fit under the bulge without scraping, to keep track of movement. After about a month, I could no longer slide the stick through without scraping. I figured the bulge had dropped another 1/8-3/16 of an inch. Fortunately, our raw clay-sand bricks had dried by then.


Lisa, one of the cooks, helps make bricks—

here she wets the brick form (1.5″ deep: scrap 2×2 — thin bricks are best for domework, as they make better curves, and their lighter weight means less risk of slippage when you’re setting them).


Next, she sprinkles sawdust (we didn’t have any sand), so the brick will slip off the board.


Throw two handfuls of mud into the form; if you throw it right, the corners come out clean and sharp.


smooth the top surface…


we learned a lot from watching Caramelo, from Oaxaca, an expert adobe-maker… I didn’t get his picture, unfortunately…


pull the form: the brick is ready to slide off onto a flat surface for drying.


here’s our stack of about 220 bricks, with form.


in mexico, they say you can tell the top of the adobe by the dog prints…


Here’s the outer surface of the oven — a thin shell containing perlite insulation. I cut a hole in the bottom side to drain out the perlite (used a sawzall — it was like cutting plywood! tough stuff!) I used a piece of old roofing tin to make a chute to direct the flow of perlite. It poured out like water. Nasty dust. A good mask is well worth the money.


here you can see the layers, from outside to inside: colored final clay-sand plaster, insulating sawdust-clay mix, and gypsum/clay-impregnated burlap


Eventually, I cut out a large, wedge-shaped piece of the entire shell. There was virtually no cracking as a result of any cutting. The shell was super-strong and rigid. Note the bamboo armature underneath.


perlite inside the shell, avalanching down to the drain hole…


Lisa peering into the emptied out shell…


good insulation! The bamboo, which was just temporary formwork for the fireproof plaster shell while it dried, is still completely intact: not even charred!


The bamboo supports a layer of burlap impregnated with clay slip and gypsum plaster for a quick-setting, stiff, and fireproof surface that could be plastered immediately.


even the jute twine that I’d used to tie the bamboo hadn’t charred—

indeed, it was barely toasted! I would guess that the temperature at that level barely got over 3-400 degrees F.

In cross-section, you can see the layers of the fire-proof shell that holds the insulation. From top to bottom: white is gypsum and clay impregnated burlap with some sandy-clay plaster, then a layer of insulating and sculptable plaster made of clay and sawdust, then a layer of fine clay-sand finish plaster.


The surface at the bottom of the photo is the top of the oven dome, made of pure sand and clay. Above that, looking like the edge of a cliff, is a layer of sawdust mixed with clay slip. This close to the heat, the sawdust gets hot enough to completely burn out, leaving an insulative clay foam. It works well, but crumbles at a touch. The white above is perlite, which was pretty well contaminated with the crumbs of crumbled clay-foam, so we had to buy new when we refilled the insulation cavity.


The thermal layer comes down. Note thickness of shell.


The dense thermal layer was not hugely massive because the oven is used primarily for pizza and just a bit of bread. However, with 6-10 inches of perlite all around, it held heat extremely well, and performed beautifully.


Thickness ranged from a bit more than three inches to almost five inches — many hands make uneven work! Bricks will correct that…


Thermal layer completely cleaned out. Note the bottles in perlite exposed around the edges of the floor bricks. The bricks on edge around the perimeter are a “bumper course” to protect the softer mud dome from peels and firewood.


Front arch


the hole in the shell was just big enough for me to step into the oven and sit on the floor. I’m very glad I didn’t have to wiggle through the door in order to work!

first courses of bricks, showing the mortar wedge that sets the angle of the dome

a wedge of bricks at the corner nearest the door helps define the line from the (low) front end of the oven to the higher rear end…


story stick shows the 16″ target height for the rear of the dome: I angled the bricks to meet the top of the story stick about 6-8″ off the back of the oven…


the mortar is just clay and sand, like the bricks. Building an oven with bricks this way means that you can use more clay in the mix; because the bricks are relatively thin and small, they shrink without cracking. The clay is generally more durable under constant use than a typical “cob” mix, which uses a higher percentage of sand to limit cracking.


at work: I was very glad when I realized I could just cut out a big doorway right through the shell. Originally I’d thought I would have to wiggle through the door and work lying down!


the walls start to close in; each course describes a slightly smaller circle and tilts at a steeper angle


I’d only ever seen pictures of this, so was both pleased and amazed at how well the mortar held the bricks against the force of gravity


getting tighter!


I had to clean the bottoms of the mortar joints by feel because I couldn’t get low enough to see ’em!


I tried to work as symmetrically as possible, but it’s definitely very different than laying up a straight wall.


toward the end, I had to enlarge the opening of the shell just to be able to maneuver.


I used the spray bottle to wet out dry surfaces to take the mortar better.


the dome closing in to the final keystone courses…


these last bricks were almost vertical, but were also held in place by being wedge-shaped. Since the bricks were raw (unfired) they were easy to cut with an old Sawzall blade.


final courses close the dome.

note the angled courses shaping the “throat” leading to the door opening

hard to clean the insides of the final mortar joints; I made a long handled tool that reached through the doorway to scrape the joints clean.

 

patching the shell was a matter of splitting some new bamboo and wedging it into place


not much structure is needed to support the burlap and gypsum plaster, which is self-supporting once it sets. However, I did “tie” the main bamboo struts with “straps” of gypsum-soaked burlap that wrapped around the bamboo and over the outside of the shell. These got trimmed after the gypsum set.


from burlap to finish plaster was a matter of an hour or so…


I started a drying fire immediately (using the old bits of bamboo for kindling—

nice and dry!)


almost ready for pizza!

Build Your Own Barrel Oven Book!

Hand Print Press has published a new book about a hybrid style of wood-fired oven called a Barrel Oven!

Build Your Own Barrel Oven
A Guide for Making a Versatile, Efficient, and Easy to Use Wood-Fired Oven

The tools for a sustainable future continue to grow! In this book, Max and Eva Edleson offer a comprehensive guide for planning and building a practical, efficient and affordable wood-fired oven. The Barrel Oven offers surprising convenience because it is hot and ready to bake in within 15-20 minutes and is easy to maintain at a constant temperature.   It can be the seed for a small-scale baking enterprise or the heart of a community’s wood-fired cuisine. All kinds of food can be baked in the Barrel Oven including bread, roasts, pizza, cookies cakes, pies, casseroles and stews. Follow this step-by-step guide to transform local, low-cost materials and the sun’s energy into good food.

Highlights include:

  • Detailed how-to instructions about how to build this style of oven including step-by-step explanations.
  • Photos and drawings that demonstrate the building process and completed ovens.
  • General discussions about siting and location for outdoor kitchens.
  • Guidance in deciding which kind of wood-fired oven is best for you.
  • Interviews with people who have been cooking in Barrel Ovens for many years.
  • Recipes for great dishes to be cooked in your Barrel Oven

More about the Barrel Oven from Firespeaking!

Praise for Build Your Own Barrel Oven:

“Eva and Max Edleson are highly skilled both as builders and as bakers, but what really shines through in this book is their excellence as communicators. They clearly present varied methods and materials, with very helpful discussions of the pros and cons of each option. Other builders’ voices really round out the presentation. This is a book that will likely inspire you to build your own oven, and make you feel like you have experienced mentors walking you step-by-step through the process.”

Sandor Ellix Katz, Author of Wild Fermentation, The Revolution Will Not Be Microwaved, and The Art of Fermentation.


“Max and Eva Edleson offer up this barrel oven as a marriage of native, natural materials with industrial “waste.” The result is a beautiful and useful appliance that combines the appeal and advantages of wood fire with the quick heat of an American industrialized kitchen.

‘What?! A wood-fired oven that can bake bread 20 minutes after you light the fire?’

Yup. And it can be cheap, too, especially if you can do simple metal work yourself. And your kids can help you do the mud work.

The more people get interested in wood-fired cooking, sustainability, and traditional ways of eating, the more important it is to have options, examples, and choices. Here’s a great contribution for back-yard bakers serving family and friends, primitive out-back chefs cooking for large groups and gatherings, or a small, wood-fired business in need of a versatile oven. Good stuff!”

— Kiko Denzer, author, Build Your Own Earth Oven: A Low-Cost, Wood-Fired Mud Oven, Simple Sourdough Bread, Perfect Loaves.