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A comparison of the EBC 9.8 method with a common applied HPLC analysis for Determining
J. Titze, V. Ilberg, F. Jacob and H. Parlar
In addition to alcohol content, original gravity and extract, bitter substances represent one of the basic criteria for evaluating beer quality. The most important bitter substances in beer are the iso-α-acids [3].Two methods for determining bitter substances in beer have become widely adopted as the methods of choice:1.European Brewery Convention, EBC 9.8 - Bitterness of Beer (IM) [1], (cf. Mitteleurop?ischen Brautechnischen Analysenkommission e. V. MEBAK 2.18.1 [2]), 2.HPLC analysis according to EBC 7.8 - Iso-α-, α- and ?-acids in Hop and Isomerized Hop Extracts by HPLC [1].EBC 9.8 is the ?wet chemistry? method for determining EBC bitter units (BU). This method measures the sum of the bittering substances by means of extraction with acidic iso-octane followed by photometric measurement at 275 nm. This analysis method measures α-acids, primarily iso-α-acids.The second method as to HPLC analysis is currently not considered a commonly used standardized method for analysing bitter substances (iso-α-, α- and ?-acids) in beer, since it is based on EBC 7.8, which uses high performance liquid chromatography (HPLC). For the method as applied herein, only the section of EBC 7.8 pertaining to the procedures for the HPLC analysis was consulted. After separation of the iso-α-acids by HPLC, the individual components were measured at 270 nm. In contrast to EBC 9.8, the HPLC analysis determines individual bitter substances rather than the sum of all bitter components.
Descriptors: Bitter substances, iso-α-acids, analysis, sample preparation, HPLC, EBC 9.8, EBC 7.8
BrewingScience - Monatsschrift für Brauwissenschaft, 59 (November/December 2005), pp. 18-24
