Water undergoes a significant change of properties in the supercritical region (e.g low dielectric constant, high ionic product). As a result, it is used as a powerful oxidant for the fast and efficient hydrothermal gasification of most organic materials, for the production of biobased products, including fuel gas (hydrogen), valuable chemicals (methanol, acetaldehyde) and energy. Water at supercritical conditions (>221 bar, >374 °C) is able to break most of the organic composite's structure, including lignocelluloses, something that is not possible with a number of other processes. In addition, this aqueous-based process would be favoured over vapour-phase processes as it overcomes the low volatility of carbohydrates and also negates the need for a dry feedstock, such as wood biomass, which would otherwise require an energy intensive drying step.