This study addresses the pressing issue of global food waste (FW) by conducting a comprehensive comparison between two conversion methods: hydrothermal carbonization (HTC) and vapor-thermal carbonization (VTC) for the production of hydrochar. The analysis encompasses physicochemical characterizations, Fuel characteristics, and surface properties. Under identical reaction conditions (180–250 °C, 30 minutes), both processes significantly elevate the carbon content of hydrochar. VTC-hydrochar with a carbon content ranging from 54 % to 62 %, while HTC-hydrochar with a slightly higher range of 55–63 %. Notably, hydrochar derived from both methods results in higher heating values (HHV) of 24.04–27.40 MJ/kg for HTC and 22.85–26.60 MJ/kg for VTC, indicating enhanced fuel quality. But with less volatile matter, VTC-hydrochar shows lower HHV. Moreover, HTC-hydrochar demonstrates superior attributes for rapid ignition and energy release, while VTC-hydrochar proves more suitable for applications requiring higher combustion temperatures and stability. In terms of surface properties, VTC-hydrochar demonstrates a higher NH4+ adsorption capacity attributed to its superior pore structure and abundant key functional groups, making it an ideal choice for adsorption applications. Most notably, through comparative analysis, finding that VTC-hydrochar with a more uniform structure from the complex and diverse FW feedstock. This study establishes a robust scientific foundation for selecting appropriate hydrochar production technologies.