How do you separate Ethanol and water?

Ethanol and water can be separated by fractional distillation. Fractional distillation separates liquid mixtures with different boiling points.

Ethanol boils at a lower temperature than water. However, it forms a boiling azeotrope with water (azeotropes occur when solvent mixtures boil at a lower temperature than the component solvents). The azeotrope boils at 77.85 degrees, whereas pure ethanol boils at 78.4 degrees. The azeotrope is 96% ethanol and 4% water by volume. This is the maximum concentration of ethanol that can be achieved by simple distillation.

Other methods of separating ethanol from water include using salts to make the water and ethanol phase-separate, using molecular sieves, using additives to change the azeotropic mixture, or distilling dry ethanol from wet ethanol that has been treated with a water-reactive metal, leaving behind the solid metal hydroxide.