I was wandering around in the garden section of a home store a couple of weeks ago and saw a variety of outdoor fire containers. They are for gentrified camp fires and are used by suburban entertainers for house parties and barbecue gatherings. They range in style from large iron bowls intended to be sunk into the ground to large ceramic stove-like urns with decorative shapes and patterned cutouts.

They came to mind while reading this page about the design of simple ceramic pots that can be used by developing world people for cooking and biochar production.

There are many ways to make biochar. Huge machines and factories can produce a lot of char in a centralised manner. But for the millions of poor farmers in developing countries, there may be a way to make char too. In an efficient, simple way. The "terra preta pot" might be just this appropriate technology.

With a "terra preta pot" you can make biochar from crop residues instead of wood, and you can use the pot at the same time to cook food or to warm the home. The pot-in-a-pot is in fact a micro-pyrolyser. It is made from local materials, and can be manufactured by any skilled potter. Thus it is possible to make biochar-generating cooking stoves while maintaining local pottery traditions. No need to import steel stoves or machines from abroad.

I wonder if the containers used at suburban camp fire gatherings might also have pots within the pots and so make a garden sized batch of char while they are hoisting a few brewskies in the evening. When they clean up the party debris on the following day the ashes and char can be sprinkled into their gardens or flower beds. It seems that there could also be stove designs that could be used for barbecuing too. If nothing else they would make charcoal that could be used for future barbecuing - a sort of breeder reactor that makes fuel while burning fuel.