Iran Bitumen is produced from selected crude oils through a process of fractional distillation. The crude oil is heated to temperatures of between 300 and 350 degrees Celsius and fed into a distillation column allowing the lightest fractions of the crude to separate, through vaporization, from the heavier fractions, which remain liquid.

The higher boiling point fractions are then drawn – off via a heat exchange and enter a vacuum distillation column. This process produces a "short residue" that is used to manufacture several grades of Iran bitumen.  The  pressure and temperature conditions  within  the vacuum  process  will  determine the hardness of the short residue, and as  such  the  grade  of  Iran bitumen produced.