The properties of wood charcoal layers have an effect on the performance of small-scale blast furnaces. In order to characterize the mechanical behavior of a fixed bed of eucalyptus charcoal, a specific uniaxial compression test was designed and used with charcoal layers of different characteristics. This layer test has the potential to be standardized, and it made it possible to consider the bulk properties of randomly layout charcoal pieces, which was better adapted than single specimen tests in the fiber direction. A total of eight charcoal layers were prepared with two carbonization temperatures (500 °C and 900 °C), two granularities (10 mm and 20 mm), and two different testing temperatures (20 °C and 300 °C). Characteristic parameters of the compression tests were then determined as the particle size distribution, the mechanical energy, and the mean power. The charcoal produced at 900 °C and with a granularity of 20 mm was more resistant to breakage than the others were, and a high quantity of large particles remained after the tests. Significant correlations existed between the carbonization temperature, granularity, and mechanical power of the compression test. The mechanical power was the main parameter that determined the resistance to breakage of a charcoal bed in compression.