Analysis of condensed tannins using acidified vanillin

Abstract
The acidified vanillin method for determination of plant tannins has been reassessed. Excluding light and controlling the temperature of the reaction mixture increased the colour stability of the vanillin tannin adduct. Selection of optimum concentrations of reactants and solvents enabled the method to be used in the range 5‐500 μg of condensed tannin with a precision and accuracy greater than 1 μg.