ELECTRONIC NOSE FOR MONITORING THE FLAVOR OF BEERS

The flavour of a beer is determined mainly by its taste and smell, whi ch is generated by about 700 key volatile and non-volatile compounds. Beer flavour is traditionally measured through the use of a combinatio n of conventional analytical tools (e.g., gas chromatography) and orga noleptic profiling panels. These methods are not only expensive and ti me-consuming but also inexact due to a lack of either sensitivity or q uantitative information. In this paper an electronic instrument is des cribed that has been designed to measure the odour of beers and supple ment or even replace existing analytical methods. The instrument consi sts of an array of up to 12 conducting polymers, each of which has an electrical resistance that has partial sensitivity to the headspace of beer. The signals from the sensor array are then conditioned by suita ble interface circuitry and processed using a chemometric or neural cl assifier. The results of the application of multivariate statistical t echniques are given. The instrument, or electronic nose, is capable of discriminating between various commercial beers and, more significant ly, between standard and artificially-tainted beers. An industrial ver sion of this instrument is now undergoing trials in a brewery.