Precipitated silica (SiO2) is industrially produced by mixing a silicate solution with acid in a semi-batch process. Polycondensation of monomeric silica leads to the formation of particles which aggregate and eventually form a particulate gel. However, this is instantly fragmented by the mechanical energy input caused by the stirrer. Shrinkage and compaction of these fragments lead to the final product aggregates. It is the aim of this study to enable tailoring of the structure and size of these product particles via the process parameters. The present paper describes the influence of the parameters temperature, ionic strength, and composition, which affect the pH, on the properties of unstirred gels regarding their elasticity and thus their fragmentation behavior. Gelation time may be qualitatively estimated solely from the concentration of the feed materials.(1)