Replacing barley malt with huskless oats optimizes extract yield.
Oats are also occasionally used to make different beverages. In Britain, they are used for brewing beer. Oatmeal stout is one variety brewed, using a percentage of oats to produce the wort. It contains a proportion of oats, normally a maximum of 30%, which are added during the brewing process.
Brewing a beverage with high levels of unmalted common Avena sativa oats has proven to be successful despite the high levels of beta-glucan, protein and fat. However, little is known about the effect of different oat cultivars on the quality and processability of the mash and the wort. So, scientists in Ireland substituted 20% or 40% barley malt with oats, and compared the mashing performance of eight oat cultivars, selected because of their low content of beta-glucan, protein and fat, or for their high starch content.
In experiments, seven husked oat cultivars (A. sativa L. Lutz, Buggy, Galaxy, Scorpion, Typhon, Ivory and Curly) and one huskless oat cultivar (A. sativa var. nuda NORD 07/711) were fully characterized using standard methods, lab-on-a-chip capillary electrophoresis and scanning electron microscopy.
During the mashing process, the researchers used a commercial rheometer to analyze the rheological behavior of the mashes, which contained up to 40% of each oat cultivar. In addition, the quality of the wort obtained from laboratory-scale mashing trials was analyzed, particularly with regard to cytolytic, proteolytic and amylolytic properties.
The scientists found that the substitution of up to 40% barley malt with husked or huskless oats resulted in significantly higher pH values, beta-glucan content and viscosity, as well as significantly lower soluble nitrogen and polyphenol content, color value, filtration rates and apparent attenuation limits. Huskless oats contained significantly less beta-glucan as well as more protein and starch than the seven husked oat cultivars. Replacing barley malt with huskless oats resulted in a constant extract yield, unlike husked oats that caused significant extract losses. Further information. Elke K. Arendt, Department of Food and Nutritional Sciences, University College Cork, National University of Ireland, Western Road, Cork, Ireland; phone: ?21-490-3000; fax: ?21-490-2064; email: email@example.com.