Abstract: Porous silicic acid having a specific surface of about 50 to 1000 m.sup.2 /g and having an anion content below the chemically determinable limit of detection is made by hydrolyzing methyl or ethyl silicate or polymethyl or polyethyl silicate with about 70 to 120% of the stoichiometric amount of water with moderate stirring.Hydrolysis activators such as acids or bases may be present as well as alcoholates of oxides of transition metals which then appear in the end product. Alcohol may also be present to facilitate hydrolysis.The products are characterized by marked purity and their specific surface can be closely and reproducibly controlled.