The Tensiograph - A Novel Instrument for the Fingerprinting and Analysis of Multiple Physical Attributes of Beer

Abstract

A brief description of the tensiograph multianalyser (formerly known as the fibre drop analyser) is given. The complex multi-measurand nature of the signal, known as the tensiotrace, is explained and a brief outline given of the methods for obtaining the most important measurands from these signals for the analysis of beer. An extensive background study has been made of the basic components of beverages using the multianalyser, which investigated the basic capabilities of the instrument for the analysis of sugars, alcohols and proteins. The most important results are summarised briefly because these define a background instrumental capability for the more complex problem of the analysis of beer. A range of commercially available alcoholic beverages has been studied with the multianalyser using matching analysis. This analysis is given in terms of match values (M-values) of the drop period, peak heights and times, point matches and area matches obtained from the comparison of experimental tensiotraces. In a study of seventeen commercial beverages it has been demonstrated that an LED multianalyser is able to fingerprint beers. Quantitative information on the physical and chemical properties of these products was also obtained. In this study it was found that two of the beers were so close in every respect of their physical properties that the LED multianalyser had difficulty in distinguishing one from the other. Results on two sets of blind tests of samples are described. The first on a set of alcohol spiked samples obtained from an industrial source and organised by Brewing Research International, Surrey was successful in obtaining measurements of the physical properties of these samples. The second blind test addressed the more difficult problem of fingerprinting various types and batches of the same product with the multianalyser. The results of these tests are presented and the difficulties experienced in conducting these measurements are explained. Finally, in the light of the work on fingerprinting, demonstration of the real capability of the multianalyser was attempted with a study of various mixtures of two beers. Difference value (D-value) analysis is used to determine the level of admixture of the two stout products employing a calibration procedure. The potential of the multianalyser technique in the area of beer analysis is reviewed.