NOVELTY - Producing a bio-product from organic matter feedstock, comprises: (a) providing a reaction mixture comprising the organic matter feedstock, a solvent, and a solid substrate; (b) treating the reaction mixture in a reactor vessel at a reaction temperature and pressure suitable for conversion of all or a portion of the organic matter feedstock into a product mixture comprising the bio-product; and (c) depressurizing and cooling the product mixture, where the solid substrate is solid or substantially solid at the reaction temperature and pressure.    USE - The method is useful for producing a bio-product from organic matter feedstock (claimed), where the bio-product is one of biofuels (such as ethanol and diesel) and platform chemicals.    ADVANTAGE - The method: recycles the solid substrate and oil; inhibits scaling in a reactor vessel during the conversion of organic matter feedstock into a bio-product; inhibits development of a pressure gradient in a continuous flow reactor vessel during the conversion of the organic matter feedstock into a bio-product (claimed); inhibits charring across reactors during the conversion of organic matter into bio-products; is safe; cost-effective; utilizes the solid substrate, thus increasing the availability of metal surfaces in the reactor that can partake in heterogeneous catalysis; provides a renewable carbon-rich solid product with suitability for use in bio-char carbon sequestration, fuel and/or chemical applications; and produces bio fuel with increased energy content and stability.    DETAILED DESCRIPTION - Producing a bio-product from organic matter feedstock, comprises: (a) providing a reaction mixture comprising the organic matter feedstock, a solvent, and a solid substrate; (b) treating the reaction mixture in a reactor vessel at a reaction temperature and pressure suitable for conversion of all or a portion of the organic matter feedstock into a product mixture comprising the bio-product; and (c) depressurizing and cooling the product mixture, where the solid substrate is solid or substantially solid at the reaction temperature and pressure, sequesters organic and/or inorganic matter that desolubilizes within the reaction mixture or the product mixture, and/or alters at least one flow characteristic of the reaction mixture and/or the product mixture in the vessel. An INDEPENDENT CLAIM is also included for a bio-product obtained by the method.