This paper describes a double-layered foam filled THz split ring resonator gas sensor. The study of resonant shifts and damping (inverse of Q-factor) of a foam filled metamaterial is conducted for the concentration measurement of acetone gas. A nanoporous cellulose foam is used for its good adsorption of gas molecules. Different dielectric inserts and multilayer metamaterials are being investigated. Results from experiment and simulation generated from the CST Studio Suite 3D EM analysis are presented. In addition, porosity of the foam optimized by fine tuning the fabrication procedure to improve the measurement is also discussed.