Vanillin production from lignin oxidation is a biomass-based process that employs a by-product of the pulp and paper industry and air to obtain a high-added value compound. However, lignin is an organic polymer with a structure that depends strongly on the source and the conditions to obtain vanillin should be adjusted for different samples. The objective of this work is to establish a fast and standard protocol to characterize lignin conversion to vanillin by batch oxidation. The experimental technique is coupled with a mathematical model that allows us to fit the data and determine kinetic rate constants under non-isothermal conditions. Two examples of vanillin oxidation with very different lignin sources are presented. The results revealed vanillin yields with respect to the lignin mass ranging from 3.5% to 7.6% for the high and low-molecular weight lignins, respectively. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.