In this episode ofBrewing Society, we explore how a humble glass of beer helped change the course of scientific history. Theodor Schwann’s discovery in 1837—that yeast is a living organism responsible for fermentation—revolutionised our understanding of biological processes and laid the foundation for microbiology. Schwann’s work bridged the gap between Antonie van Leeuwenhoek’s discovery of microbes and Louis Pasteur’s germ theory, ultimately leading to breakthroughs in food preservation, disease prevention, and industrial brewing.