Abstract: A method for producing a partially hydrolysed lignocellulosic material is provided including treating a lignocellulosic material with an acid and/or an alkali and then a polyol. Also provided are methods of producing a fermentable sugar, or a fermentable sugar and a fermentation product from said partially hydrolysed lignocellulosic material. A partially hydrolysed lignocellulosic material, a fermentable sugar, and fermentation product produced by such methods are also provided. Also provided is an apparatus for producing a partially hydrolysed lignocellulosic material, such as by the aforementioned method.