![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
Beer flavor compounds of routine interest were analyzed by gas chromatography using either direct headspace injection or solvent extraction. The headspace chromatographic method described here makes it possible to analyze dimethyl sulfide, ethyl acetate, propanol, isobutanol, isoamyl acetate, isoamyl and amyl alcohols, and less volatile compounds such as ethyl caproate (168°C) and ethyl caprylate (208°C) in less than 20 min. Two calibration methods are described: daily calibration or the use of an internal reference beer system, which considerably simplifies the calibration procedure for long-term use. Although rapid and accurate, headspace analysis discriminates against the less volatile compounds. A complementary chromatographic method, both quick and simple, was designed to assay amounts of caproic, caprylic, and capric acids; β-phenyl-ethanol; and β-phenylethylacetate in fermenting wort and beer. In combination with headspace analysis, this method using hexanol as the extracting solvent yielded beer aroma profiles similar to those obtained with the carcinogenic solvent CS2. Repeatability of the two solvent extraction procedures was studied by replicating the analyses. The combined techniques were used to investigate relationships between flavor compounds and their formation in 48 lager beers.