This study evaluates the environmental sustainability of yogurt production by comparing factory-produced (FPY) and homemade yogurt (HMY) in Türkiye. It challenges the assumption that small-scale production is inherently superior to industrial systems. Using a novel dual-reference approach, the research investigates resource-to-nutrient conversion efficiency across scales, specifically quantifying the environmental burdens of delivering essential protein to consumers. A comprehensive “cradle-to-grave” life cycle assessment (LCA) was conducted in accordance with ISO 14040/44 guidelines. Primary inventory data for industrial production (FPY) were collected from a dairy facility in Ankara, Türkiye, while home production (HMY) data were experimentally derived using a commercial yogurt maker. Environmental impacts were modeled in SimaPro 10.2 using the ReCiPe 2016 Midpoint (H), Cumulative Energy Demand, and AWARE v1.07 methods. To rigorously evaluate how industrial concentration influences performance, dual functional units were employed: 1 kg of yogurt and 10 g of protein, based on mass balances identifying protein densities of 4.77% (FPY) and 3.97% (HMY). Finally, the reliability of the results was validated through Monte Carlo analysis and sensitivity scenarios assessing the carbon intensity of the electricity supply. Per 1 kg of product, HMY exhibited higher environmental burdens in most categories, including global warming (4.95 kg CO2-eq/kg), due to the suboptimal energy efficiency of domestic appliances. Conversely, FPY showed higher water consumption (2.17 m3/kg) from industrial cleaning and packaging. When normalized per unit of protein, FPY’s environmental advantage became more pronounced; its higher protein concentration, achieved through optimized evaporation, resulted in more efficient raw milk and energy utilization. These findings suggest that avoiding industrial packaging in HMY is frequently offset by high operational energy demands, leading to burden-shifting in carbon-intensive energy contexts. FPY provides a more sustainable pathway for nutrient delivery than HMY under current conditions. Environmental performance is highly sensitive to the functional unit choice; mass-based metrics fail to capture the superior nutritional efficiency of industrial processing. Modern home-based production does not guarantee a lower ecological footprint, especially in regions with fossil-fuel-dependent energy grids. It is recommended that future food LCAs move beyond mass-based metrics to include nutritional quality indicators. For the dairy sector, decarbonizing the electricity supply and improving farm-level efficiencies remain critical. Consumers should be informed that the sustainability of homemade yogurt is contingent upon appliance efficiency, and introducing energy efficiency labeling for these devices could serve as a practical tool to guide sustainable consumer choices.
Fidan et al. (Tue,) studied this question.