Roasting is a type of light pyrolysis of biomass at temperatures between 200 and 320°C, which changes biomass properties and enhances its quality as a fuel for combustion and gasification applications. This technique provides a dry product with no biological activity such as decomposition. Combined with densification, roasting creates a high energy-density fuel product.

HECO technology can fluidise smaller biomass particles than other current technologies, and gives an effective energy transfer to the roast, so as to ensure that material is evenly treated. This reduces the holding times required to roast materials, and thus uses much less energy than other technologies, resulting in lower operating costs.