Sn-doped and undoped barium titanates pressed powder pellets were sintered at 1360 and 1390 degrees C for 5 h. Though batched to form Ba2Ti9O20, a two-phase microstructure of BaTi4O9 and TiO2 formed from the undoped system. The dielectric constant at 6 GHz was 40 without SnO2 additions. Doping with 1.64 mol % SnO2 stabilized Ba2Ti9O20 and formed a single-phase microstructure but resulted in higher porosity. Dilatometry studies implied that SnO2 additions facilitated a greater fraction of reaction to occur in the solid state, causing a lower quantity of pore-filling fluid to form above 1317 degrees C. As a result of the higher porosity, the dielectric constants and quality factors were also reduced.