Patagonian Gall (IMAGE) University of Wisconsin-Madison Caption Patagonian galls such as these harbor a parent of the hybrid yeast used to make lager or cold-brewed beer. Credit Diego Libkind, Institute for Biodiversity and Environment Research Usage Restrictions Credit Diego Libkind, Institute for Biodiversity and Environment Research License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.