AbstractPalm oil, palm stearin, hydrogenated palm oil (IV 27.5) and hydrogenated palm olein (IV 28) were crystallized at 5°C, temperature cycled between 5 and 20°C, and kept isothermally at 5°C for 36 days. The polymorphic state of the fats was monitored by X‐ray diffraction analysis. Soft laser scanning of X‐ray films was used to establish the increase inβ crystal content. Palm stearin was least stable in theβ′ form, followed by palm oil. The hydrogenated oils were very stable in theβ′ form. Differential scanning calorimeter (DSC) analysis was used to complement the X‐ray data.