Cooking with gas is a luxury. The tiny spikes of blue flame surrounding a gas stovetop is a convenience to which few have access. Most people burn wood, and the smoke emitted in the process kills millions of people a year. (1)
Smoke is toxic. A wood fire is fueled by some 213 different gas compounds that are released when the cellulosic material of the wood is heated. (2) Some of these gases are ignited and burned away, while the rest of the gases cool and condense into smoke. Which means that smoke is nothing but a farrago of unburned chemicals.
There are two ways to avoid smoke when cooking: ventilation and cleaner burning. Ventilation is easy to grasp since we all know about chimneys and range hoods. You give the smoke somewhere to go.
The other way to ward off smoke is to prevent its formation by creating fires that burn at a higher temperature. This requires a healthy supply of oxygen. The more oxygen a fire has the more power it has to burn away gases before they condense into smoke.
Third-world kitchens are often built in roofed enclosures. The enclosure protects the fire from the elements, but it also provides no route for the smoke to escape. Enclosures also restrict airflow, which chokes the burning process and makes for smokier fires. The combination of restricted airflow and improper ventilation creates an environment guaranteed to have an injurious effect on the women who daily labor to make food and the children who assist them.
We have seen kitchens like this in El Salvador. We have witnessed our neighbors laboring in an environment that—often without them knowing—is paring away their health. It’s time we do something.
We have already begun to address this issue in East Africa through an ingenious piece of technology called a rocket stove. The rocket stove combines both methods of smoke avoidance. It’s equipped with a chimney for ventilation, and it’s designed to burn intensely and efficiently. The result is a healthier and more efficient way to cook. (3) With the help of our cooperatives, we have built more than 300 rocket stoves in Kenya, and around 40 more in Uganda. Our friends in Africa, especially the women who daily cook, have been enthusiastic about the functionality of the stoves. (Read More.)
I sat down with Michael Johnson, who will be heading up the rocket-stove project in El Salvador this summer, to ask him a few questions about the implementation of the project in El Salvador.
What are the materials and the costs of building a rocket stove? Will we be able to use local materials?
All the materials can be found locally. The materials are going to be red brick, which they produce in the area… mortar to hold the bricks together… and we will also use ash as an insulator, which we can get from previous fires. The stovepipe is just thin piece of metal that we’ll be able to bend and send up through the roof. Probably the hardest material to get will be the cooking plate, which is just a slab of metal. We should be able do the project for under 40USD. [Read more on our focus on what is local, affordable and duplicable here.]
How many rocket stoves are we planning to build in El Salvador this summer?
We’re planning on building two to start. One of our neighbors is very excited about the project, so we will begin there. She [the neighbor] has always been willing to be ingenious. We are still planning where the second one will be built.
How different is the process of cooking with a rocket stove? Do you see any difficulty in getting people to adopt this new way of cooking?
I don’t see any difference. They like to use a circular plancha [griddle] that is made out of clay. And we can make something just like that. We can change the design to make it a more natural cooking experience. But a lot is the same. They cook with wood, and the rocket stove uses wood.
Other than the control of smoke, does the rocket stove have any other benefits?
It burns less wood. The guys have had a lot of success building them in Africa. And that’s just a simple design. They love it. For us, if we can prevent the amount of wood they have to carry on their backs from one place to another—and they’re mostly women—we can really help impact physical lives.
They have these small trees around their property, sucker trees, and they grow fast. They would have never thought about using these for fuel before. They’re just too small. They're just these one-inch sticks. [with the Rocket Stove] they could actually use that as a fuel source.
(1) WHO estimated in 2012 that 4.3 million people died from smoke inhalation. WHO (2014), Household Fuel Combustion. http://www.who.int/indoorair/publications/household-fuel-combustion/en/.
(2) Howard W. Emmons and Arvind Atreya (1982), The Science of Wood Burning. Proceedings of the India Academy of Science, Vol. 5 (4), pp. 259 - 268.
(3) The stove was designed by Dr. Larry Winiarski at Aprovecho Research Center (ARC). If you are interested in some of the more technical aspects of the design, see: Larry Winiarski (2005) “Design Principles for Wood Burning Heating Stoves.” http://www.aprovecho.org/lab/pubs/arcpubs. There is a lot of variations on the original design, but the basic principles remain consistent from design to design.