Abstract
Circular brewing approaches aim to reduce waste, recover resources, and improve sustainability across malt processing, fermentation, cleaning, and packaging operations. This study examines circular strategies for recovering spent grain, yeast biomass, and process water in brewery systems. Brewery by-products were assessed for fibre recovery, protein reuse, residual sugar extraction, yeast biomass stabilization, nutrient recovery, water recycling, and process integration. The results show that spent grain can support fibre-rich material recovery and secondary fermentation streams when drying and enzymatic treatment are controlled. Yeast biomass showed potential for protein-rich recovery, repitching, and nutrient recycling after viability and contamination screening. Process water reuse reduced freshwater demand when filtration and sanitation standards were maintained. The study demonstrates that circular brewing requires coordinated recovery pathways rather than isolated waste treatment. Integrated by-product and water management can reduce operating cost, environmental load, and raw material loss while supporting sustainable brewery production.