A process of mass transfer is described which utilises latent heat transfer with little or sensible heat transfer. In a preferred process microbubbles are used under certain conditions of contact with a liquid phase to ensure highly effective mass transfer between a gaseous and liquid phase with significantly less than expected or little or no sensible heat transfer. The present invention in part provides a means by which the known state of a cold liquid of varying depths can be changed using a hot gas injected via a micro bubble inducing internal mixing without allowing the resultant mixture to reach equilibrium thereby ensuring the transfer process becomes continuous. Thus a process is described wherein at least one gaseous phase is contacted with at least one liquid phase such that the heat ratio of the system (AA) is maintained at an a value of greater than 0.5, and the mass transfer is effected by passing a gaseous phase comprising microbubbles through a liquid phase of thickness no more than 10 cm.