Recent developments in high gravity beer-brewing

Beer-brewing under high gravity (HG, specific gravity of 13-18 degrees P) and very high gravity (VHG, specific gravity of 18 degrees P) wort conditions has a wide range of benefits, from improved process economics to reduced environmental impact. This review highlights the research developments in HG and VHG brewing over the last 10 years. New research emphasizes the importance of multifaceted strategies to achieve comprehensive development in HG brewing. As the brewing yeast is exposed to a variety of stresses (e.g., osmotic stress, ethanol stress) during HG conditions, stress-alleviating strategies have been the prime focus of researchers. Studies have focused on mitigating nitrogen limitation, promoting inexpensive brewing adjuncts, and realizing the potential of exogenous enzymes in HG brewing. In addition, recent studies have addressed the importance of hybrid and mutant yeasts as well as yeast flocculation and immobilization under high specific gravity conditions. Furthermore, studies to unravel yeast physiology under HG brewing and process modelling have received much attention.