Interactions of molecular additives with amorphous solid water have been investigated using time-of-flight secondary ion mass spectrometry and temperature programmed desorption. The crystallization temperature of water on a clean graphite substrate decreases from the bulk value of 160K to 150K when water deposition temperature increases from 20K to 100K. This phenomenon is induced by the formation of a specifically oriented water layer at the interface, as evidenced by that a submonolayer of n-hexane adspecies on graphite quenches this behavior. Thermal desorption spectra of additives reflect their hydration forms. The n-hexane molecules are trapped in the interior of a porous water film via hydrophobic hydration and released explosively during crystallization. The thermal desorption spectra of methanol resemble those of water from multilayer films because methanol can enter the hydrogen-bond network of water via hydrophilic hydration. The hydration of formaldehyde is hydrophobic in nature despite the presence of the polar carbonyl group. Features of both hydrophilic and hydrophobic hydrations are identifiable in acetone-water interactions; the branching ratio depends on the water preparation method and substrate. (C) 2015 Elsevier B.V. All rights reserved.