The process is for pretreating a lignocellulosic biomass feedstock and comprises: soaking a lignocellulosic biomass feedstock wherein the soaked biomass is present as a mixture with a free liquid and wherein the free liquid comprises at least one dissolved compound selected from the group consisting of glucose, xylose and respective oligomers thereof, washing the mixture of the soaked biomass and the free liquid, wherein at least a portion of the free liquid containing at least one dissolved compound selected from the group consisting of glucose, xylose and respective oligomers thereof is separated from the soaked biomass to create a soaked washed biomass and at least one free liquid stream, compressing the soaked biomass to create a released liquid, separating the released liquid from the soaked biomass, and keeping at least a portion of the released liquid separate from any free liquid.