The evaluation of wort by near infrared spectroscopy

Near infrared spectroscopy (NIS) has been used routinely for many years for the measurement of grain protein and moisture in plant breeding programmes. Investigation as to the applicability of NIS to the identification from a barley breeding programme of the progeny with high malting quality potential was carried out over several harvests. The project concentrated on the determination of correlations between Hot Water Extract, Total Soluble Nitrogen, and Free Alpha Amino Nitrogen contents of worts (the extract of malt used to make beer) and NIR transmission data using the multivariate method of partial least squares regression. The correlation coefficients, for both calibration and prediction data sets, were significant and the standard error of prediction was similar to that obtained in the standard methods in the first year, but were unsatisfactory in the second. The instrument chosen for the study gave satisfactory correlations for the purpose of selection in the intermediate generations of the breeding programme with errors similar to the analytical methods, as long as a very wide range of calibration samples were collected from more than one harvest. It was shown that the use of an NIR spectrophotometer as a selection tool for malting quality within a barley breeding programme would not be sufficient to justify investment in this type of instrument for this purpose alone