Build this easy adobe cooker in a weekend.
To heat the oven: Build a fire inside and keep it going for about three hours.
My husband and I first spied an outdoor bread oven while strolling through our neighborhood. The beautiful brick dome was situated at the end of an overgrown driveway. It was so intriguing that we knocked on the house’s door and met the oven’s owner – a frail Italian granny. She graciously shared her story, which was inseparably intertwined with the oven.
“We came here for the coal mines in the ’20s,” she said, “You couldn’t get good bread here, not like in the old country, so we built this oven. All the neighborhood ladies would get up early to start their bread dough, and I’d be up by 4 to fire the oven. It took five hours to heat that oven, and it was big enough to hold all the loaves. We’d drink tea, gossip and bake our bread. During the summers, some of the men went up to the mountains to herd sheep. I’d go up there to make them bread. I built ovens up there out of clay dirt and baked bread every few days. Those men could eat a lot of bread!”
The woman’s fascinating story motivated us to research outdoor bread ovens, with the goal of building one for ourselves. Clay is readily available at our place and was our material of choice. After some serious research and with help from the best adobe-oven-making book ever, Kiko Denzer’s Build Your Own Earth Oven: A Low-Cost Wood-Fired Mud Oven, we gave it a try. (The book is available at www.Grit.com.) Using Denzer’s thorough, friendly instructions, I built an oven in our yard, several ovens for the local school district and one for a mountain-man rendezvous. This year, my husband and I built the more refined model covered in this article out in our pasture.
This oven only takes about three days to build, start to finish, working a couple of hours a day.
Although you can build them on the ground, we decided to raise our new adobe oven to a convenient working height. For simplicity, we built a foundation for the oven using concrete blocks held together use a construction adhesive such as Liquid Nails©. Since Liquid Nails isn’t technically a load-bearing mortar, you won’t want to build your base more than about three blocks tall. Depending on their size, it will take about 30 concrete blocks to build the foundation’s perimeter walls. Once the adhesive has set, fill the container with rubble (broken pieces of concrete, big rocks, etc.). Top the rubble with gravel and sand, to about 8 inches below the rim. Next, add a 5-inch layer of vermiculite or perlite for insulation. And, finally, top this layer with sand; tamp it level with the top of the blocks (see Figure 1).
You will build your oven’s fires on a layer of firebrick. Place the bricks on the sand and kiss them together, tapping with a rubber mallet to straighten. If they don’t go down perfectly, just pick them up and try again. On our oven, we elected to cover the whole top of the foundation with firebrick.
Our base was about 4-feet square, so we used a string and pencil to scribe a 28-inch-diameter circle for the inside of the oven and a 42-inch-diameter circle for the outside. You will want to adjust those values somewhat if your base has different dimensions than ours. Just be sure to leave enough space to allow 7-inch-thick walls on your completed oven (see Figure 2).
Shape a lovely dome with wet sand and be sure that it fits inside the smaller of the two circles. Take your time to make it gorgeous, and spray lightly to keep the sand wet. This shape will create the interior of your oven. Before you go on to the next step, measure the exact height of the dome and make a note of it. You will need this figure later.
The ideal mud mixture for an adobe oven is 25 percent clay and 75 percent sand. Shovel three measures of sand onto a tarp and add a single measure of clay initially. If your clay consists of a clay/soil mix, add proportionally more to the sand. Mix the materials together thoroughly – we used our bare feet. Periodically pick up the corners of the tarp and roll the adobe to the center and mix again. Continue adding and mixing components until the proportions look and feel right. You should be able to hear the sand “bite” as you roll the mud in your hand. Periodically test the mud by making a golf-ball-sized sphere and dropping it from your waist onto a hard surface. If it breaks apart, the mud is too dry, if it flattens significantly, it is too wet. Add small amounts of water or clay/sand to correct for high or low moisture content.
Place brick-sized lumps (approximately 3 inches wide) of adobe around your dome, building up as you go. After completing one row, add another right on top of it. Continue until you have completely covered the sand dome with a 3-inch thick coating of mud (see Figure 3). If the adobe slumps some during the process, use an old knife and slice off the excess adobe on the bottom. Use a short piece of 2-by-4 to “rock” over your adobe to smooth and adjust any distortions in the form.
Let the first adobe layer set overnight. If it stiffens up nicely, you should cut the door before building the second layer. If it is still quite soft, you can wait until the second layer is done to cut the door. If the mud seems too soft and wet, your mix may need more clay. For our oven, we realized our mix was not drying hard and it needed clay, so we pulled the whole thing off and remixed the adobe. It was an easy fix.
Mix adobe for the second layer as before, but add some chopped straw to it, to hold it together and help prevent severe cracking. Chop your straw with a weed-whacker in a wheelbarrow or trash barrel and mix the chopped straw into your adobe as you make it. The second layer is built just like the first, up and over. Use the 2-by-4 to rock over the form once more (see Figure 3).
Mix up some wet, soft adobe, using more clay than sand and very finely chopped straw, which you make by running the weed-whacker longer in the straw in your container. If you have some pretty clay, perhaps red, use it for your plaster. Enjoy spreading it evenly over the entire surface of your oven.
In North America, traditional ovens tend to have doors that are 63 percent of the height of the oven’s interior, so multiply the height of the dome by 0.63 and cut your door that high, using a large kitchen knife. (Be sure to make it wide enough to allow convenient access.) Remove the sand, using a trowel and your hands. Gently scrape the sand from all the interior surfaces and brush it off the brick floor (see Figure 4).
Trace the shape of your oven’s opening on a piece of paper, and cut a piece of wood to fit the shape. It doesn’t have to be perfect but try to get it close. Fashion a handle from a scrap piece of wood or buy one and attach it to the door.
It can take weeks for your oven to dry, but you can speed the process by building small fires to help it along. Some cracking is to be expected during this process and as you use the oven, bit if large cracks develop, fill them with damp clay.
Light a large fire built with sticks and small pieces of wood inside the oven. When it dies down, build another. Continue this process for about three hours. While it is heating, make your dough.
Any good bread recipe will work in your adobe oven. (See Adobe Bread Recipe for one suggestion.) Use an oil-free recipe for a crispy, European crust. Let the bread rise, punch down, and form into round or long loaves. For the final rising, place loaves on cornmeal-covered cookie sheets.
Remove all the ashes and unburned wood from the oven. Nail or screw a rag to a stick, wet the rag, and “scuffle” out the bricks so they’re clean. Let the oven sit or “soak” for about 10 minutes. Wet an old piece of towel and wrap the door with the towel inside. In a few minutes, remove the door and towel.
Gently place a risen bread loaf on your peel (the shovellike tool for moving bread). Put the peel into the oven and with one sharp jerk forward, slide your bread right onto the hot bricks. Repeat with all your loaves (see Figure 5). Close the door, using the wet towel as a seal. Let bread bake according to your recipe, but pay attention with your nose and intuition to know when it’s done.
You will be tempted to cut into your loaves immediately, but let them sit and cool for 10-15 minutes. Your bread finishes baking as it cools. Now you can cut it or tear it, add butter or other toppings, and enjoy crisp-crusty European bread, fresh and perfumed, from your own adobe oven.
You can cook anything in your oven, including meats and vegetables, pies and pizzas. For pizza, prepare your pies to put into the hot oven right after you scuffle out the ashes; don’t soak the oven. For meats and vegetables, put in a covered pot after the soak. Remove the cover the last 15 or 20 minutes. Cook pies in a pie tin, but try to avoid fruit spilling over onto the brick floor. Of course, anything you wish to cook in the oven has to fit through the door.
Cover the oven during rain or snow. If you build an open-sided shed around your oven, it can last for years. If food sticks to the oven floor, you may need to scrape it out once in a while.
Cathy Wilson teaches art and writing in a juvenile correctional facility in Utah. She has written several books on alternative health and education. She and her husband – and sundry children – live and garden on three acres in the high desert.
More than 150 workshops, great deals from more than 200 exhibitors, off-stage demos, inspirational keynotes, and great food!LEARN MORE