Substrate characterization experiments have been carried out on different feedstocks and structure materials considered appropriate for use in dry anaerobic batch digestion systems. Physical and biochemical material characteristics tested were density (bulk and saturated bulk density, compressed density), permeability, compactibility, water holding capacity, maximum water content, and volatile solid content. Oedometer tests have been conducted on prepared feedstock/structure material mixtures targeting a high permeability under compression. The compactibility values of the tested materials ranged from 5.81% and 58.33% and material permeability values ranged from 2.48E‐5 m s‐1 and 2.32E‐4 m s‐1. Porous materials such as straw and woodchips were tested to determine if they enhance material mixture properties to yield superior permeability and allow percolation.