Building an outdoor cob oven is a great way to add a fun and practical cooking space to your outdoor area. The cob oven is built using natural, unprocessed materials such as clay, sand, and straw and is both an interesting and sustainable way to cook food.
The great thing about building a cob oven is that it is relatively simple, and can be completed in just a few days if you have the right materials and a bit of expertise. Here’s what you need to do:
First, you’ll need to prepare the materials for your oven. You will need mud, sand and straw. Melted down mud or clay, “slush”, can be used to bind the materials together; if you don’t have access to clay, you can also use hydrated lime.
To start, you’ll create a foundation base with the mud, and use the sand, straw, and water to create cob mixtures to build the walls.
Once your foundation and walls are completed, you can begin building the top of the oven, or the oven dome. Start by creating a circular dome form for the top out of sticks, sand, and mud. Next, you’ll need to create an opening, or a “lip”, at the base of the dome where the fire will sit, so you can also make sure that the lip is slanted to help with air flow.
Use the cob mixture that you made to cover the dome and the lip and create a solid, compact surface.
Next up is the insulation layer. To insulate the oven, you’ll need to create a “hot plate” to put on top the oven. This is usually done by spreading straw and clay on the oven dome and then covering it with sand and clay.
The insulation layer will absorb and disperse the heat to cook your food.
Finally, you can cover the outside of the oven with a clay and sand mixture to give it a final sleek and secure finish. You can also add decorations such as mosaics and paint to give it an even more personalized look.
And there you have it – an outdoor cob oven that’s ready for some al fresco cooking! Now, all you have to do is wait for the oven to cure, light the fire and let the cooking begin!
What is a cob oven used for?
A cob oven is a wood-fired oven made from a mixture of clay, sand, straw, and water called “cob. ” These ovens are traditionally used to bake bread, but can also be used to bake pizzas, cakes, pies, or any other food that you’d typically bake in a conventional oven.
The advantage of using a cob oven is that it reaches high temperatures quickly and can retain the heat for an extended period of time. This makes cob ovens very efficient and ideal for large-batch cooking, such as with a group of friends or family.
Cob ovens also have an interesting aesthetic and often feature creative designs, making them an interesting addition to any outdoor kitchen space. Additionally, the high temperatures can be used to smoke meat and fish, which adds an interesting flavor to the food.
How hot do cob ovens get?
Cob ovens generally heat up to around 500-600 degrees Fahrenheit when they are being used for baking. This temperature is ideal for baking many types of bread, pies, and other items. The heat from the oven works to create a crispy exterior to the baked goods and a soft interior.
Additionally, wood burning ovens create their own unique flavor which adds a delicious element to the food. Some people enjoy using wood burning ovens because the heat does not dry out the food, as could happen when using other cooking methods.
The heat also works to draw out flavors from the ingredients that would otherwise remain dormant when using other cooking methods.
Can you make a pizza oven out of cob?
Yes, it is possible to make a pizza oven out of cob. To build a cob pizza oven, you will need materials like cob, a metal barrel or metal drum, bricks, and ledge stones. The cob is the main material used to make a cob pizza oven, as it helps insulate the oven and hold in the heat.
To start, you will want to dig out a shallow pit and lay down a layer of bricks. This will act as the foundation, which the metal barrel or drum will sit on. Then you will mix cob and water together to form a thick consistency and start stacking the cob around the drum, to a height of about two feet.
The thicker the cob layer, the better. You will then want to install the ledge stones, which will act as a surface to place the pizza on when cooking. Lastly, you will be ready to fire it up and start baking your delicious homemade pizzas!.
How much straw do I need for a cob oven?
How much straw you need for a cob oven will depend on the size and shape of the oven you are building. Generally speaking, you will need enough straw to fill the interior space of the oven – the space between the sand-clay mixture that forms the dome of the oven and the firebrick lining.
This space should typically be filled with 4 to 8 inches of straw insulation. The best way to determine how much straw you need is to measure the interior volume of the oven and then multiply that number by the amount of straw you plan to lay.
For example, if the total interior volume of your oven is 6 cubic feet and you are filling it with 6 inches of straw, then you would need 36 cubic feet of straw for the oven.
Where can I find clay to build a cob?
Clay for building a cob can be found in many places and depends on what type of clay you want to use. If you want to use the traditional and easily sourced clay, then you might try a local garden center or hardware store.
Chances are they will have some variety of clay you can use.
Another option is to source it online. Depending on where you live, there may be different options available to you. For instance, if you live in the United States, websites like gardeners. com and soil3.
com both have a variety of organic and all-natural clays available for purchase. If you live in the UK, websites such as theclaymineralltd. co. uk and clayworks. co. uk both offer clay products.
A more sustainable but often more difficult option is sourcing it locally. Depending on your location, you may be able to find clay either through local farmers or through small businesses near you. You may also be able to find clay in lakes, rivers, or mud flats, but it is important to be respectful of the environment when sourcing clay this way.
How long does it take to heat a cob oven?
Heating a cob oven typically takes about 3-4 hours. The time can vary depending on the size and shape of the oven, the type of fuel being used, the weather, and other variables. To heat a cob oven, add the fuel (wood or charcoal) to the firebox, light the fire and wait for the oven to heat up.
A good estimate is that it will take between 1.5 to 2 hours for the oven to reach a temperature of about 32-43°C (90-110°F), 1 hour more to reach 57-71°C (135-160°F), and an additional 30 minutes to reach temperatures of 93-110°C (200-230°F) if you are going to cook food.
After that, your cob oven should be ready to use.
Does a cob oven need a chimney?
No, a cob oven does not need a chimney. This is because the fire that is used to heat the oven is kept inside the oven rather than in a separate space, such as a chimney. This means that the exhaust from the fire simply escapes out of the top of the oven, as the temperature of the oven gets higher over time.
The dome structure of the oven also helps to deflect some of the heat, away from the oven and up into the air. Furthermore, the cob material used to build the oven can help absorb some of the heat and prevent it from escaping too quickly, allowing the oven to be able to effectively reach very high temperatures.
What kind of clay do you use for a cob oven?
Cob ovens are traditionally built with clay-based material mixed with sand, straw and water, known as “cob. ” This type of mixture provides insulation, allowing the oven to be used in a variety of climatic conditions.
The clay used when building with cob is typically a local type, such as shale, volcanic ash, clay or red earthenware. The grain size and thickness of the clay can vary depending on the application. When building a cob oven, a balance needs to be sought between plasticity, which allows the clay-sand mixture to be formed by hand, and strength, which allows the oven to withstand the heat of the fire.
In general, the more plastic the clay is, the less strength it will have, and vice versa. It is usually best to experiment with some test batches to determine the ideal combination for the desired application.
Is cob water resistant?
Cob is a natural building material that is composed of clay, sand, straw, and often water. As it has a high content of clay and sand it is inherently water resistant however its resilience to water can be tested and improved with proper, regular maintenance.
As cob is a soft material, it is susceptible to moisture and needs to be sealed to increase its water resistance, such as painting it with a sealant or waterproofing the exterior of it. In addition, cob can be protected from water damage by covering exposed cracks and holes, and regularly checking for threats from moisture intrusion.
Finally, the use of weatherproofing additives is another effective way to provide your cob building with added water resistance.
How do I waterproof my cob?
The best way to waterproof your cob is to use a breathable membrane. This typically consists of a perforated, semi-permeable layer of material that is placed between the cob and a protective, waterproof coating.
To properly install the membrane, ensure that it is clean and dry, then attach it to the cob base. Once it is secure, apply a sealant over it to further protect against water penetration. Additionally, it is important to maintain the integrity of the cob by regularly checking for cracks, chips, or other damage and patching them up before water can seep in.
Finally, it is recommended to apply a top coat of paint or sealant at least once a year to keep your cob waterproof.
How do you protect your cob from rain?
In order to protect your cob from rain, a number of steps can be taken. First, it is important to take a good look at your existing structures, as well as the landscape, and take steps to limit any water damage.
This could include inspecting the roof and structure for any areas where water could collect and steeping the cob to divert any water away from the building.
If you do not have an existing roof overhang or roof structure, it may be wise to consider constructing one as an effective method of protection. This could include a wood or metal frame covered with a sheet material or an open-air canopy that is either covered with straw or can hold a water resistant fabric such as canvas to prevent rainfall.
Along with a roof overhang or canopy, do not forget to consider your wall systems to help protect from rainfall. This could include constructing a structure with a dedicated rain gutter system that can be filled with straw or gravel in order to collect and divert any water away from the cob walls.
It is also important to keep your cob walls in good condition to better protect them from rain. This could include inspecting and filling any existing cracks or weak areas with cob and adding a lime-based plaster to the cob walls as a protective coating.
Adding a waterproofing agent to the outer layers of the cob, such as a clay slip, will also help to further protect the cob from rainfall. Finally, never forget to keep your gutters, downspouts and drainage ditches clear of any debris or dirt that could interrupt the flow of water away from the structure.