The Application of the DESIR Technique to the Analysis of Beer

The Dry Extract Spectroscopy by Infrared Reflection (DESIR) technique was used to predict bitterness, total soluble nitrogen and free amino nitrogen concentrations in beer. Spectra were recorded of the extracts of 65 beers and calibration was attempted using multiple linear and partial least squares regression on raw, derivative and transformed data. High correlations and low errors of prediction were obtained using the DESIR technique for the analysis of free amino nitrogen and total soluble nitrogen. However, poor correlations were observed between NIR spectral data and bitterness values. The technique was shown to be a rapid, repeatable and accurate alternative to traditional methods.