The processes in the course of crystallization of powders prepared by solution combustion synthesis have been investigated. Solution combustion synthesis has been accomplished using aluminum nitrate nonahydrate as oxidizer and alanine as a fuel. In the course of synthesis samples with various ratios of alanine to nitrate (fuel-lean, stoichiometric, and fuel-rich) have been used. Differential thermal and thermogravimetric analysis (DTA/TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used for investigation of powders obtained by solution combustion synthesis. Influence of fuel to oxidizer ratio on composition and thermal evolution of powders prepared by synthesis have been described. It was shown that combustion reaction ignition time, combustion rate and achieved temperature depends upon the nitrate to alanine ratio. The sample with the most fuel ignites first, burns fastest and reaches greatest temperature. However, it was established that combustion reaction was more complete, leaving less organic residue, in sample with the most oxidizer. It has been shown that amorphous powder crystallizes to γ-alumina around 800 °C, while its slow transformation to α-alumina commences around 1000 °C. Regardless of fuel to oxidizer ratio, thermal treatment at 800 for two hours was sufficient to prepare porous γ-alumina. Thermal treatment at 1000 °C for two hours yields with complete transformation of γ- to α-alumina.