VIEW ARTICLE    DOI: 10.1094/ASBCJ-53-0167

Electronic Aroma Detection in the Brewery (1). J. B. Tomlinson, I. H. L. Ormrod, and F. R. Sharpe, Whitbread PLC, Whitbread Technical Centre, Park Street, Luton, Bedfordshire, LU1 3ET, U.K. (1) Presented at the ASBC Annual Meeting, San Diego, CA, 1995. J. Am. Soc. Brew. Chem. 53(4):167-173, 1995. Accepted May 10, 1995.

The analysis of the aroma of various beer and raw material samples has been undertaken using a multi-element array of chemical sensors—an electronic nose. Studies included the investigation of several beer, hop, leaf, and malt samples. Multidimensional analysis of mean instrumental odor intensity and normalized pattern responses led to increased discrimination among samples with the formation of "family" clusters, i.e., specific groups relating to sample types. The analysis of lager and ale brands resulted in the formation of an instrumental aroma spectrum with a degree of overlap between some brands. The introduction of diacetyl and metallic off-taints to a lager caused the depression of overall instrumental aroma intensity. It was suggested that these "spikes" affected the general level of volatiles rather than specifically reacting with the sensors. The phenolic spike behaved quite differently. The instrumental aroma of various leaf hops resulted in a discrimination being observed between a control and mildew-infected samples as well as among different grades of a single hop variety. The instrumental aroma of several malts showed differentiation among standard white ale "micromalts" from four barley varieties, among peated malt samples containing various levels of phenolic residues, and among malt types. The significance of instrumental odor intensity, its position when displayed within a mathematically calculated map, and the degree of scatter are discussed. Keywords: Detector, Odor, Sensor, Sensory analysis