How can destearinating animal fats produce both hard fat and liquid oleo oil?

Destearinating, also known as winterizing, is a process used to separate high-melting glycerides from animal fats like tallow. This separation is achieved through a controlled cooling process, which allows the high-melting glycerides—referred to as stearine—to form crystals large enough to be removed from the mixture via filtration or centrifuging.1

By performing this separation, processors can simultaneously produce two distinct products:

• Hard fat: The solid stearine fraction, which is high in stearic acid content and utilized for specialized applications such as candle making.1
• Oleo oil: The remaining liquid oil fraction, which is separated from the solid components.1

This method relies on the physical properties of glycerides, where those with a higher proportion of saturated acids generally have higher melting temperatures and solidify more readily than those containing unsaturated acids.2