Inulin is considered as an attractive feed for the synthesis of 5-hydroxymethylfurfural (HMF), an important biobased platform chemical with high application potential. We here report a systematic study to optimize the HMF yield from inulin in a batch reactor for reactions in water using sulphuric acid as the catalyst. The latter was selected on the basis of a screening study with seven organic- and inorganic Bronsted acids (H2SO4, HNO3, H3PO4, HCl, trifluoroacetic acid, maleic acid and fumaric acid). The effect of process conditions such as temperature (160-184 degrees C), inulin loading (0.05-0.17 g/mL), sulphuric acid concentration (0.001-0.01 M) and reaction time (0-60 min) on HMF and levulinic acid (LA) yields were determined experimentally and subsequently modeled using non-linear multivariable regression. The highest experimental HMF yield was 39.5 wt% (50.6 mol%) and was obtained at 170 degrees C, an inulin loading of 0.17 g/mL, a sulphuric acid concentration of 0.006 M and a reaction time of 20 min. Agreement between experiments and model for both HMF and LA yield was very satisfactorily. (c) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.