Why settle? A review of timely and premature brewing yeast flocculation

Why was the work done: Yeast flocculation is an important parameter in brewery fermentation, as beer quality is affected by the onset and intensity of cell aggregation. Malt induced premature yeast flocculation (PYF) is described as a rapid decline of yeast cells in suspension during fermentation even in the presence of sufficient nutrients. Though occurring only sporadically, premature yeast flocculation can represent a significant risk to brewery operations. What are the main findings: This review considers the known and suspected mechanisms underlying both normal and abnormal flocculation. Particular effort is made to propose definitive methods for the detection of PYF and to summarise potential strategies to alleviate premature yeast flocculation, with emphasis on relevant approaches for industrial brewing. Why is the work important: Recent research has provided new insights to elucidate the mechanisms involved in premature yeast flocculation, though a complete understanding has yet be reached. Given the association of PYF with poor field conditions during barley growth, it may be expected that climate change will contribute to an increase in the frequency or severity of PYF. This review is intended to serve as a resource for further research on the topic as well as development of practical prevention or mitigation strategies.