A distillation process that operates at a reduced pressure. The effect of the low pressure is to reduce the boiling point temperature of the mixture being separated. This is useful where the materials may be heat-labile, such as the separation of volatiles from fruit juices, or prevent the decomposition or cracking of materials being distilled in crude oil distillation. In the vacuum distillation of petroleum fractions, residues may be used as the feedstock for cracking other products, or may be blended to produce fuel oil or asphalt. See molecular distillation.