Hot water extract (HWE) is one of the key quality attributes considered when determining the malting performance of barley. The international malting and brewing industries utilise standard procedures for measuring HWE, including European Brewery Convention (Analytica - EBC 1998), Institute of Brewing (IOB - Methods of Analysis 1997), and American Society of Brewing Chemists (ASBC - Methods of Analysis 1992). EBC and ASBC procedures are similar and use a multi-temperature programmed mashing profile, while the IOB procedure uses a constant temperature infusion mashing profile. In Australia, maltsters and brewers generally use the EBC procedure to determine extract levels on commercial samples. Specific quality goals for developing Australian commercial barley varieties include a high extract carbohydrate potential with a desired level in excess of 82% EBC fine grind, dry basis (MBIBTC, 2001).
Malting quality testing protocols vary in public Australian barley breeding programs especially in early generation testing where significant quantities of grain may not be available. Different methodologies are used including NIR and small-scale assays developed in-house. A review of the barley quality evaluation laboratories in 1995 by the Grains Research and Development Corporation (GRDC) included a recommendation of implementing standardised methodology for micromalting and quality testing of advanced material (Enright et al., 1995). The Australian Barley Chemists Group (ABCG) incorporating members of barley quality evaluation laboratories in Perth, Adelaide, Horsham, Wagga Wagga and Toowoomba, meet formally on an annual basis to discuss testing protocols and quality issues. The objective of method standardisation is to develop small-scale methods to provide breeding programs and industry groups with MBIBTC equivalent results from within the breeding programs. In 1999, a diastase method was standardised by the ABCG and correlated to the EBC industry method (Fox et al., 1999). Due to sample quantity limitations in some stages of a barley breeding program, a small-scale EBC HWE procedure has been developed and collaboratively evaluated by the participants of the ABCG.