In a method for monitoring the correspondence of a beer sample with a reference beer, at least 15 reference beer samples of the reference beer are brewed with the same ingredients and the same process parameters. Measurement signals for the absorption spectrum of the reference beer samples are captured and a principal component analysis is carried out for the measurement signals, in which at least 15 principal components are ascertained. A factor loading PR(i,j) is respectively determined for each principal component for the individual reference beer samples and a reference value (I) is ascertained, where i denotes the reference beer sample and j denotes the principal component, μR(j) refers to the mean value of all factor loadings of the j-th principal component and σP(j) refers to the standard deviation of these factor loadings. A reference interval (II) is formed, where n denotes the number of reference beer samples, m denotes the number of principal components, σR(j) denotes the standard deviation of all reference values of the j-th principal component and k denotes a constant not equal to zero. A measurement signal is captured for the absorption spectrum of the beer sample and the factor loadings PB(i) of this measurement signal are determined for the principal components ascertained for the reference beer samples and a characteristic (III) is formed and compared to the reference interval. Should the characteristic B lie outside of the reference interval, a fault during the production of the beer sample is indicated.