EVALUATION OF A MALTING BARLEY QUALITY ASSESSMENT SYSTEM

New malting barley varieties are annually tested for their malting and brewing potential according to a field trial set-up combined with qua lity evaluation on pilot scale. To assess the effects of trial year an d location on quality evaluation data, a data base consisting of quali ty data from Dutch malting and brewing trials of new malting barley va rieties during the period 1989-1995 was analyzed using multivariate st atistical techniques. It was also determined which parameters gave lit tle or no discrimination among varieties over the years. The analysis showed that strong annual effects occurred over the period observed. A considerable list of 23 analytical parameters from barley, malt, wort , and beer analysis were relevant to explain 50% of the variance in th e data set. Seven parameters showed hardly any variation and possessed no discriminative value. This indicated that the number of parameters could be diminished to some extent without losing resolving power wit h respect to quality evaluation. A further reduction is possible when, of two parameters showing high positive or negative correlations, onl y one is analyzed. Quality data from different trial locations were pr one to annual effects. The trends observed showed clustering of data f rom particular trial locations with discrimination among locations in certain years. From this evaluation, it could not yet be concluded whe ther or not a limitation in the number of trial sites is feasible. The evaluation offers an approach towards further increasing the efficien cy and cost-effectiveness of existing trial systems.