Although biology is a very practical science, high school biology teaching often remains dry and heavily reliant on theoretical knowledge. Our project explored how practical approaches can be integrated into the classroom by using culinary microbiology, or kitchen fermentation, as a low-cost and accessible model system. Fermentations can break these boundaries by allowing students to practically explore concepts ranging from classic microbiology and experimental design to metabolism, biofilm formation, microbial interactions, food webs, and experimental evolution. This is possible because microbiota are simple and cheap to maintain, require little equipment, grow quickly, and necessary ingredients are available in supermarkets. The project was split into two phases. In phase one, an interdisciplinary group of 10 students was introduced to the theoretical and practical basics of microbiology. We also invited speakers from local food safety enforcement and health departments, as well as a European food safety biotech company. Over the following weeks, the group explored seven fermentations through planned experiments, student-designed experiments, and low-cost growth-medium design and testing. After each unit, students evaluated engagement, simplicity, and suitability for a high school classroom. Based on this feedback, three fermentations were selected for phase two. Phase two involved 11 mainly master’s students from life sciences and biology education and focused on developing final teaching units. These were tested as case studies in two Berlin secondary schools, with one class at each school and 14–16 students per class. The focus shifted from fermentation itself to fermentation as a model for biological concepts, including wild strain isolation and characterisation, selection media design, longitudinal growth, carbon source and competition assays. The final school visits addressed cohabitation/cross-feeding interactions, biofilm formation, and stressor-induced fitness effects in kombucha. Day one focused on developing hypotheses and experimental setups, while day two was reserved for taking measurements and interpreting the results. Feedback from students and teachers was highly positive, and teachers stated that they planned to include these or similar units in future teaching.