Its a question that gets asked of me on a frequent basis.
Torrefaction of wood dates back to the Second World War. The technology was created to assist in converting biomass into a coal-like material to help achieve better fuel quality for combustion. Once biomass is torrefied it becomes dense and was commonly converted into briquettes or pellets. Some of the advantage’s of this technology over traditional heating sources was the ability of the biomass to repel water to a greater degree thus being able to be stored for considerable amounts of time without risk of added moisture.
Thermally modification of wood seeks similar results by reducing the woods ability to take on moisture. This increases the woods durability which in turn provides extended life due to the reduction of the wood becoming acceptable to mold or rot. Thermal modification alters the cell cavity within the wood resulting in the reduction of the woods ability to accept and release moisture through its life cycle. There are many end uses for thermally modified wood with exterior decking and siding products being more popular choices.
Both technologies are similar in the means of producing a permanently reduced moisture content within the product while eliminating biological activity like rotting. In both cases the process of achieving increased product performance has been obtained through each process. Research and development of both technologies continues to advance today allowing for multiple use applications.