Abstract: The present invention relates to a process for the conversion of a lignocellulosic feedstock involving acid pretreatment. The process comprises the steps of treating the lignocellulosic feedstock with alkali at a pH of between about 8.0 and about 12.0 so as to dissolve acetyl groups present on said lignocellulosic feedstock, while converting less than about 10% of the xylan present in the lignocellulosic feedstock to xylose and less than about 10% of the cellulose to glucose, thereby producing an alkali conditioned feedstock. The alkali conditioned feedstock is then pretreated at a temperature of about 160° C. to about 250° C., at a pH of about 0.5 to about 2.5 for about 0.5 to about 10 minutes so as to hydrolyze about 80 to 100% of the xylan and about 3 to about 15% of the cellulose to produce an acid pretreated feedstock comprising cellulose. The cellulose in the pretreated feedstock can be hydrolyzed to glucose with cellulase and the glucose can be fermented to produce a fermentation product.