Baking cobs in cob: our double chambered wood fired oven

Once upon a time in the UK we set up a really good bakery. We used organic ingredients. We made slow fermented Real Bread. We engaged our local community by working on a ‘bread club’ Community Supported Bakery model. We raised all the funding to move from a home kitchen Ikea oven, to a pizzeria pop up bakery, to a 15m2 mini bakery at the back of a grocery and finally to a whopping 280m2 bakery/cafe/baking school only from people in our community. No banks. We set it up as a worker cooperative and by the time we left The Handmade Bakery 6 years later to move to Spain, there were 17 very capable, motivated people working with us. 


A really good bakery, a permaculture bakery. Just it had one thing missing right at its centre… 

A woodfired oven. 

So this time we had to build one. And every year we harvest a LOT of sticks from pruning our orchards so along with woodchip compost and biochar, wood fired cooking makes total permaculture sense.

Researching the options our natural inclination was towards ‘rocket stove’ technology but I couldn’t find a single example of a rocket bread oven that could consistently bake professional quality artisan bread. We have high expectations! So eventually I came across a hybrid technology that incorporates the clean burning efficiency of rocket stoves with tried and tested earth oven technology. 


Double chambered cob ovens have a fire / bake chamber and a chimney chamber unlike most cob ovens. The principle being that smoke from the burning wood gets reignited when it flows back into the chimney chamber thus taking full advantage of the energy available in the wood. So you need two doors; a metal one while the fire is burning and a second wooden one that forms a tight seal to keep the heat in the baking chamber.

The developers of this oven style, Ernie and Erica Wisner, state that from a two hour burn you can cook for up to 8 hours. starting with pizzas or flat breads, moving on to loaves of bread then roast meats or veg and finally using overnight heat to culture yoghurt, toast granola, dry preserve fruits or veg. 

We are yet to cook for eight hours but we have made really good pizzas and fabulous sourdough bread. And we’ve made it big enough that we can start teaching slow fermented artisan baking here at Finca Slow from next spring! Watch this space...


If you fancy making your own double chamber oven you can download detailed instructions from or learn to bake real artisan bread via our online course here: