A method for the conversion of cellulosic material into ethanol and other products, comprising at least cellulose material, lignin, hemicellulose and ash, a method in which the cellulosic material is cleaned and subjected to continuous hydrothermal pretreatment without acid addition or bases or other chemical products, which must be recovered, and method in which a liquid and a fiber fraction are produced, the fiber fraction being subjected to liquefaction and enzymatic saccharification, including the ethanol fermentation method and the recovery of the product, the method comprising: - performing the hydrothermal pretreatment by subjecting the cellulosic material to at least one soaking operation, and transporting the cellulosic material through at least one pressure reactor defining a pressure zone of the reactor to a high pressure； the cellulosic material is heated to a temperature between 170 and 230 ° C and the cellulosic material is subjected to at least one pressing operation, creating a fiber fraction and a liquid fraction； - in which the temperature and residence time for hydrothermal pretreatment are selected at a lower severity than that required for pretreatments that seek maximum elimination of the hemicellulose from the fiber fraction, so that at least 80 % of the lignin content of the cellulosic material before pretreatment in the solid state fiber fraction； - the discharge of the pressed fiber fraction from the reactor pressure zone to a closed downstream zone, which is at a lower pressure than the reactor pressure zone, while collecting the released steam without the access of air； - the discharge of the liquid fraction from the pressure reactor to a second closed zone, which is at a lower pressure than the pressure zone of the reactor, while collecting the released steam without the access of air； - said pressing of said cellulosic material taking place while said cellulosic material is still under pressure or after at least one pressure reactor has
