Biochar

Post-carbon alchemy

Biochar is an ancient-like material that is receiving increasing attention due to its beneficial uses in mitigating climate change. It was first discovered in terra preta, a highly fertile soil used over 2000 years ago in the Amazon basin. Biochar is produced by heating biomass in an environment with very little oxygen (pyrolysis), resulting in a highly porous product capable of absorbing water, nutrients, and promoting microbial colonization. Primarily, the material is used to improve soil quality while simultaneously storing carbon in the long term.

During her residency period at Domaine de Boisbuchet, supported by Acción Cultural Española, the artist constructed and installed a pyrolysis kiln for the production of biochar. Inspired by the principles of adobe construction, she crafted a new material primarily using the biochar produced with the kiln, along with a mixture of local soil and straw. The result of her material research was a collection of functional sculptures with potential applications in the fields of bioremediation and thermal regulation. Due to the material composition, the pieces can be reintegrated into the soil once their purpose has been fulfilled.

With this ongoing research, Carla Alcalà envisions a near future in which communities have organised themselves to construct habitable spaces from their own organic waste, which they transform into biochar. These spots function as climatic shelters that attract diverse species, including animals, humans, birds, and insects.

Making process

1. Produce your own biochar with a pyrolysis kiln (you can refer to the open-source design of the Kon-Tiki kiln from the Ithaka Institute.) or obtain it from a local supplier.
2. Grind the biochar until you obtain grains of around 3mm.
3. Mix with local soil and dry vegetal fibres until you obtain a consistent texture you can work with.

Text submitted by the maker and edited by the Future Materials Bank. For information about reproducing (a part of) this text, please contact the maker.