A number of samples each of 4 beer brands produced at 6 different plants were taken at approx. weekly intervals. Beer aroma compounds were determined by Freon 112 extraction followed by capillary column GC. Results were examined using a number of multivariate analysis procedures. Some consistent patterns in the results were found that were partly or completely successful in characterizing either the beer brand or the plant of production. SIMCA, discriminant, and Bayesian analyses were particularly effective in deriving successful classification rules. Greater differences were observed between samples of different brands than between samples originating in different plants. It was of interest to note which compounds were important in making the distinctions observed and to consider whether they might result in significant flavour differences.