In this paper we examine the conditions required to extract different types of sedimentary organic matter with subcritical water. Our aim was to develop a replacement for organic solvents for the extraction of organic matter from any mineral matrix and therefore produce a method that can be applied to materials such as soils, recent sediments and sedimentary rocks. Sedimentary organic matter of types I, II and III have been subjected to various temperatures and pressures. Diversity in polarity of organic compounds within some sedimentary organic matter types suggest that ne-tuning the dielectric constants of water provides the opportunity for selective extraction that could eliminate post- extraction fractionation steps prior to further analytical steps.