Abstract: The biomass log fuel has not been commercialized due to difficulties in mass-producing the logs at low cost. The current invention solves this problem by introducing a three-step compaction process: pre-compaction, final compaction, and ejection. While a rotary feeder/compressor is used to perform pre-compaction, a ram driven by a toggle mechanism performs final compaction rapidly and efficiently. A press implementing the three-step compaction is designed and described. This invention should improve the cost-effectiveness of biomass solid fuel or feedstock. Biomass materials such as yard waste, corn stover and switchgrass are compacted at high pressure to form dense “biomass logs” without binder or heat. Biomass logs serve as a solid fuel for heating buildings, and as feedstock for bio-reactors for liquefaction or gasification. Densifying the uncompacted fluffy biomass reduces space needed for storage, decreases the number of vehicles needed to transport biomass, and increases the energy density of fuel.