The biochar project was created by Ithaka researchers Hans-Peter Schmidt and Paul Taylor, who named their invention after the South American God of Sun and Fire “Kon-Tiki” in a tribute to Thor Heyerdahl. In 1946, the Norwegian explorer built and sailed half of the Pacific in a raft made only out of materials and with tools native to South America to prove that people journeyed to the Polynesian Islands in handmade boats. Schmidt and Taylor also took a leaf out of our ancestors’ book and wanted to demonstrate how biochar used to be produced. They refer to their concept as the democratisation of biochar production, which can provide farmers all over the world with the ability to turn their organic waste into soil-enriching coal without complicated technology.
The creation of biochar is a carbon negative process as the biomass we burn, old vines and wood, is reused instead of decaying and producing methane and nitrous oxide as would otherwise occur when left to its own devices. We add the biochar to compost which charges the biochar with nutrients such as nitrogen and potassium. The resulting compost mix is then spread throughout the vineyard to allow the vines to absorb micronutrients more easily.
The biomass is placed into an open-topped cone-shaped kiln and lit from above so that the combustible gases produced ascend through the fire. The flame is extremely clean since the wood vapours are directly burned rather than condensing in the cool air above. Due to the conical shape of the chamber, the warm air travels down the sides of the kiln and back up through the burning mass as the wood carbonises below.
About twenty minutes before the last layer is burned, we open the water tap at the bottom of the kiln. Water meets the hot coals before evaporating and rising through the centre of the chamber. The water can be drained out through the same tap to produce quench water which can be sprayed on crops to discourage fungi and snails due to its high pH caused by ash and pyrolysis oils.