A range of cesium doped silica samples (0.15 - 0.90 mmol g(-1)) have been characterized using a combination of deuterium exchange and adsorption of acetic acid. FTIR results show a strong correlation between the carboxylate formation on acetic acid adsorption and catalyst activity. Cesium loadings of > 0.3 mmol g(-1) do not give any increased acetic acid adsorption, suggesting a saturation of the silica exchange capacity. Deuterium exchange studies demonstrate that 35% of the surface silanol groups on the fresh silica are rapidly exchanged with deuterated water at room temperature.