The present work concentrates on the first step in the production of silica aerogels, the sol-gel transition. The effects of various solvents, concentration of catalyst, mol ratio solvent: catalyst and temperature of geling on the gelation time and outlook of alcogels are reported. The alcogels were prepared from tetramethoxysilane using 5 solvents with different chain lengths and ammonium hydroxide as a catalyst. It was found out that the gelation time was decreased with the concentrations of catalyst. The increase of the temperature from 20 up to 50 degrees C resulted in the reduce of the gelation time for approximately twice. The shortest gelation time was obtained for methanol as solvent. The model for the calculation time for different contents of solvent (MeOH) and catalyst (NH4OH) was developed.