When comparing results from unwashed and washed biomass it can be said that, in general, ethanol production is favoured by washing. Hoyer et al. (2013) reported that direct simultaneous saccharification and fermentation (SSF) of the whole slurry from steam pretreated spruce resulted in a low overall ethanol yield (3.9%). However, washing the slurry prior to SSF, to remove the inhibitors present in the raw material and those formed in the pretreatment step, increased the overall ethanol yield to 77.2%. In this work, the greatest difference was found between samples C and CW, due to the high concentrations of soluble inhibitory compounds generated by dilute alkali pretreatment. Unwashed and washed samples from pretreatment D showed a smaller increase of 7.9% in ethanol concentration, and both trials showed good results. Consequently, the washing stage may not be strictly necessary when applying alkaline peroxide pretreatment (Saha and Cotta, 2006).