Why can't simple distillation produce anhydrous ethanol, and what does this mean for industrial costs?

Why can't simple distillation produce anhydrous ethanol, and what does this mean for industrial costs?
Ethanol and water form an azeotrope at roughly 95% ethanol by weight, where the liquid and vapor compositions become identical. Below this concentration, ethanol evaporates preferentially, but above it, water is favored. This means conventional distillation, even with multiple stages in a rectification column, cannot exceed the 95% purity ceiling. Breaking the azeotrope requires additional processes such as azeotropic distillation with entrainers, molecular sieves, or chemical dehydration using agents like anhydrous potassium carbonate. This extra step significantly raises production costs. In the reagent market, 95% ethanol is commodity-priced, while anhydrous ethanol commands a substantial premium, and purity levels beyond 99% escalate in price dramatically. For industrial buyers, understanding this purity threshold is essential when sourcing ethanol for solvent, pharmaceutical, or fuel applications.