Rocket Stove: Oven, Griddle, Smoker in One Experiment

Creativity and a willingness to try
What we did and what we are learning.

 

        

 What’s a rocket stove?
“A rocket stove is an efficient and hot burning stove using small-diameter wood fuel. Fuel is burned in a simple combustion chamber containing an insulated vertical chimney, which ensures almost complete combustion prior to the flames’ reaching the cooking surface. It uses the same principle as the Dakota fire pit.”
https://en.wikipedia.org/wiki/Rocket_stove

Dreaming of an outdoor kitchen, with a love of earth building and appropriate technology we came up with the idea of doing a rocket stove: oven, griddle, smoker. Now I combed the web and could find one design at the time for a oven/ griddle …so we built upon that idea http://www.firespeaking.com/portfolio/rocket-fired-griddle-oven/.  I love being outside and enjoy cooking and the idea of being able to do it without heating up the house has been a great motivation….especially as canning season approaches.

Why a rocket stove?
Rocket stoves burn 18-35% more efficiently than an open fire which = less fuel. We have lots of twigs and limbs from pruning our maple trees to use as fuel. An outdoor kitchen like this provides a way to put an existing onsite material to work.

There is quite a difference in knowing what you want to do and having the details worked out to actually execute it. Plus we had a few items to do first…like build the patio.

 

We pondering this project for  months…collecting odds and potentially helpful ends from the scrap metal yard and friends. I was hoping to be able to build most of the project out of reclaimed materials. We were lucky enough to get some free bricks, an old keg from a friend (thanks J.C.), some scrap pieces of pipe from work, and some stainless scraps from my brother. I did end up buying a few concrete blocks, some firebricks, clay and lime. We got all our materials together and dry stacked it to get an idea of how it would work. Check out the video below.

Video of a fire showing how the smoke moves through the system before it is covered up

Seeing the oven draw how it was intended with no plaster was super exciting! And so…the plastering began.  I mixed a small amount of lime into the clay/sand/hemp/straw mix to help make it more resistant to weather.

Video of first firing after it was plastered

There has been some cracking where the metal meets the clay/brick areas, nothing terribly concerning…more character. The second firing did not heat as quickly as the first…quite a big difference in temperature over time and I am not sure why. I painted the lower oven door (old water meter cover from the scrap yard/ cast iron) with a high heat, clear coat paint supposed to be good up to 2000 degrees Fahrenheit…however, when the oven got up to 450 degrees according to my thermometer it began to melt—-YIKES! We don’t want to put food in there until it is remedied. We need to add a grate to the firebox to increase airflow and possibly add a damper to the chimney to be able to capture more heat. We are adjusting different elements and will continue to tweak them to learn the best way to cook on it.

Ants seem to love the plaster—-we already had lots of ants in the area due to the maple trees.

Now looking back at http://www.firespeaking.com/portfolio/rocket-fired-griddle-oven/, I can see they didn’t plaster except between firebricks—which eliminates cracking and the griddle overlays the whole top which is convenient for cleaning and you don’t have to worry about the sides (interface between the metal and plaster), easy to tilt for rain to fall off. Once we actually start cooking on ours…I will let you know the pros and cons.

All in all….still a fun learning curve!