Aerogels, with low density and high porosity, are promising materials for applications in food packaging, energy storage, thermal insulation, and water treatment [1]. This study introduces a sustainable method for producing carbon-based aerogels via hydrothermal carbonization of accessible precursors. Samples with CaCl₂ and glucose at mass ratios <2 were placed in PTFE-lined autoclaves and heated to 220°C. After cooling, the solid products were recovered and analyzed using XRD, SEM-EDX, FTIR, and UV-VIS DRS.At temperatures above 146 ºC, glucose liquefies, dissolving CaCl₂ and forming a viscous mass that decomposes above 200 ºC, releasing water vapor and CO₂, which expands the melt. The aerogel’s volume remains stable unless bubble coalescence collapses the foam. Experiments show that without CaCl₂, the carbon structure is nearly non-porous. Adding CaCl₂ creates a porous structure with a maximum pore size of ~40 micrometers at a CaCl₂/glucose ratio of 0.5. The average pore size decreases by over 50% as this ratio exceeds 1.8. XRD spectra also reveal CaCO₃ formation from CO₂ reacting with molten CaCl₂, with solid particles reducing pore coalescence by increasing viscosity. The study presents a novel method for producing carbon aerogels in a closed environment through thermal decomposition of glucose–calcium chloride mixtures. By adjusting the CaCl₂ : glucose ratio, the average pore size can be controlled, enabling formation of either non-porous amorphous carbon or closed-cell aerogels. Higher CaCl₂ concentrations result in smaller pores due to increased viscosity and enhanced surface tension of the melt. In conclusion, the development of tunable pore size aerogels through the controlled synthesis of carbon aerogels offers significant potential for a wide range of applications. These materials have the potential to revolutionize fields like energy storage, catalysis, environmental remediation, and biomedical engineering. This work was supported by a grant of the Ministry of Research, Innovation and Digitization, CCCDI-UEFISCDI, project number PN-IV-P8-8.3-PM-RO-BE-2024-0004 within PNCDI IV.