NUMAR Información General | Processes Palm oil and palm kernel oil refining is a physical process divided into the following steps: STORAGE: Raw or refined oil normalization stage for maintaining the proper stock for a steady and efficient process. Tanks are designed to protect the raw material against degradation through nitrogen blanketing and circulation systems that maintain homogeneity. BLEACHING: The removal of harmful substances that might affect the oil’s stability. Among them are: pigments, oxidation related products, gums (phosphoric compounds), moisture, and trace amounts of metals (iron, copper). DEODORIZATION: This last step in the refining process consists of removing the most volatile particles including: free fatty acids, glycerol, oxidation products, sterols and others, through steam dragging at elevated temperatures and in an absolute vacuum. FRACCIONATING: This process separates the oil into liquid and solid fragments, by gently cooling the oil to foster the development of crystals.  These crystals are then filtered at high pressure.  The liquid portion that emerges is called “olein” and the solid portion that remains is called “stearine”.