Abstract: A method is described for the preconditioning of an adsorbent, such as activated carbon, prior to charging the adsorbent into a reaction vessel of a vapor recovery system. The method includes the steps of (1) treating the adsorbent in order to establish in the adsorbent a residual heel of vapor of the type to be subsequently adsorbed in vapor recovery processing and (2) adding the treated and, therefore, preconditioned adsorbent to the reaction vessel of the vapor recovery system. In this way vapor recovery system downtime is significantly reduced.