Technical Session 05: Malts and Grain Session
Birgit Schnitzenbaumer, School of Food and Nutritional Sciences, National University of Ireland, University College Cork, College Road, Cork, Ireland
Co-author(s): Jean Titze and Elke Arendt, School of Food and Nutritional Sciences, National University of Ireland, University College Cork, Cork, Ireland
ABSTRACT: The use of oats (Avena sativa L.) as an adjunct in brewing has not only the potential to reduce the costs of raw materials, but also to contribute to a unique beer flavor and aroma. However, the replacement of malted barley with unmalted oats can also have a negative impact on the quality and processability of mashes, worts, and beers. The aim of this study was to evaluate the mashing performance of unmalted oat cultivars used as adjuncts in brewing. For this purpose, seven husked oat cultivars (Buggy, Curly, Galaxy, Ivory, Lutz, Scorpion, Typhon) and one naked oat cultivar (NORD 07/711) were fully characterized using confocal laser scanning microscopy, lab-on-a-chip capillary electrophoresis, and standard methods specified by the Mitteleuropäische Brautechnische Analysenkommission, European Brewery Convention, or American Society of Brewing Chemists. Furthermore, the rheological behavior of mashes containing 0, 20, and 40% oats of each cultivar was monitored during mashing by applying a Physica MCR rheometer. The quality of worts obtained from laboratory-scale mashing trials has been determined, particularly with regard to their cytolytic, proteolytic, and amylolytic parameters. All analyses were carried out in triplicate. Significant differences between the studied oat cultivars with regard to their use as brewing adjuncts were revealed. It has been found that naked oats are characterized by a significant lower beta-glucan content and a higher starch content in comparison to husked oat cultivars. In addition, the replacement of 20 or 40% malted barley with naked oats resulted in a constant extract yield, whereas the use of up to 40% husked oats led to significant extract losses.
Birgit Schnitzenbaumer successfully completed an apprenticeship as assistant tax consultant and worked in this job full-time before she studied brewing and beverage technology at the Technical University of Munich in Weihenstephan, Germany. During her studies, she completed several internships in breweries and did her master’s thesis on the effect of malting on the protein profile of proso millet (Panicum miliaceum L.) at the School of Food and Nutritional Sciences of the University College Cork, Ireland. Birgit graduated with a Dipl.-Ing. (M.S.) in brewing and beverage technology in 2009 and started her Ph.D. project on the application of novel and industrial enzymes when brewing with unmalted cereals at the University College Cork in November 2009.
