Multi-plant beer flavour quality monitoring.
Rehberger, A.J., Cutaia, A.J. and Heirtz, Q.A.
The system developed by the Schlistz Brewing Co. for monitoring the flavour quality of their beers throughout their different breweries is composed of 3 parts: (1) a flavour profile method in which 14 flavour terms are used, (2) a training scheme for taste panel members and (3) a method of reporting and evaluating the trial results. The 14 terms selected for the flavour profile are fruity, hoppy, bitter, malting, hang, tart, oxidised, grainy, medicinal, sulphur, bacteriol, yeasty, diacetyl and mouthfeel. Corresponding to each of these terms, there is a test beer. Those for bitter, diacetyl and tart, for example, have quinine sulphate, diacetyl or tartaric acid respectively added to beer whilst for the term hang, imported beer is employed. Panel members are trained to use these flavour attributes with different levels of addition of the various compounds being added to beer to provide varying intensities. Beers are stored at 45 degrees F for at least 16 hrs before tasting and the order of tasting is varied from day to day. A standardised form is used for tasting with the 14 terms above being listed together with a scale from 0 to 9 as follows: 0 or 1 imperceptible, 2 or 3 slightly perceptible, 4 or 5 moderately perceptible, 6 or 7 strongly perceptible, 8 or 9 extremely perceptible. Overall flavour acceptance is also scored 0 to 9, 0 or 1 unacceptable, 2 or 3 poor, 4 or 5 fair, 6 or 7 good, 8 or 9 excellent. Results on score sheets are conveyed to a central computer which holds all information concerning sample, producing plant, storage, processing, test data, taster etc. Routine reports are generated from the information on a regular basis. These give average scores and standard errors for each of the 16 attributes. Other reports can also be prepared from the results for particular beers produced in different plants to allow monitoring for uniformity and consistency.
Keywords: beer flavour quality