This paper describes the effects of different harvesting techniques and processing time delays on the yield and quality of the protein extracted through biorefining from a grass-clover mixture grown in Denmark. Two harvesting methods were employed—mowing and chopping—with subsequent processing occurring immediately or after 6 or 12 hours. The extraction process produced protein concentrates with crude protein (CP) and amino acid (AA) contents equivalent to soybean meal (SBM). This research underscores the importance of harvesting method selection and timely processing in maximising protein extraction efficiency and digestibility. The results advocate for enhanced logistics and handling practices in biorefining operations to improve efficiency and resource utilisation in protein production.