Three processes for the pretreatment of Miscanthus x Giganteus were compared, namely, dilute sulphuric acid treatment, an ethanol organosolv treatment and a two-step protocol involving a presoaking step prior to the ethanol organosolv treatment. The pretreatment assays were evaluated and compared on the basis of their Combined Severity factors. It was shown that the organosolv processes permitted an efficient removal of both lignin and hemicelluloses from the solid residue. A presoaking step prior to an organosolv process performed at low severity permitted to enhance the removal of lignin and hemicelluloses and the recovery of hemicellulose sugars.