Variations in free fatty acid content, moisture, and oxidation level can affect transesterification efficiency and fuel quality. High FFAs may cause soap formation, reducing yield. Oxidized oil can lower oxidative stability of the biodiesel. The GlobeCore USB plant includes oil pre-treatment options and precise chemical dosing, ensuring high conversion even with variable oil input. Consistent processing helps produce biodiesel that meets EN 14214 and ASTM D6751 standards, despite fluctuations in oil quality.