The surface properties of commercial grade calcium hydroxide were studied by nitrogen adsorption isotherm analysis, FTIR spectroscopy (KBr transmission and reflectance) and TGA analysis before and after toluene adsorption. Experimental results show that the surface texture of calcium hydroxide is little affected despite the relatively high amounts of adsorbed toluene and that the organic molecules are strongly bonded onto the solid, and on internal surfaces which are accessible through slit-shaped openings.