We reported on new insights into cyclodextrins as supramolecular encapsulating agents by elucidating the structure and energetics of the complexes they form with phenolic acids. We carried out gas-phase studies monitored through mass spectrometry that allowed us to work in solvent-free conditions. We determined the relative binding affinities associated with these processes, as well as the unusual complex stoichiometry observed in the gas phase for a series of phenolic acids with α-CD, β-CD, and γ-CD. We propose an explanation of these uncommon stoichiometries through solvation effects involving the cyclodextrin host as the solvating species.