Raffinose is a trisaccharide with a galactose molecule attached to the glucose side of a sucrose moiety. The high similarity with sucrose implies that the presence of raffinose in the crystallization step of sucrose from beet-sugar molasses can severly hamper the process. To shed some light on the interference of raffinose in the crystallization of sucrose, we propose to study its peculiar hydrogen bonding pattern in the crystal, based only on intermolecular interactions, as a function of temperature. Comparing the hydrogen-bonding features in raffinose to those for sucrose, will provide some hints on the solute-solvent interaction and the action mechanism of raffinose as an impurity in the crystallization of sucrose.