Optical measurements and pattern-recognition techniques for identifying the characteristics of beer and distinguishing Belgian beers

A miscellaneous assortment of 86 beers was characterized using non-destructive, rapid and reagent-free optical measurements. Diffuse-light absorption spectroscopy performed in the visible and near-infrared bands with the use of optical fiber spectrometers was tested innovatively to gather turbidity-free spectroscopic information. Furthermore, conventional turbidity and refractive index measurements were added in order to complete the optical characterization. The scattering-free near-infrared spectra provided a novel and straightforward turbidity-free assessment of the alcoholic strength. The entire optical data set was then processed by means of multivariate analysis in a search for a beer grouping in accordance with the characteristics and identity of each type. The results indicated that optical technologies could be successfully used for beer differentiating between several classes of beers. Moreover, since half the beers were typical Belgian beers, multivariate processing of the optical data was also applied in order to achieve a differentiation of the Belgian beers as compared with all the others, thus demonstrating a potential method for authenticating the country of production.