The Discovery of Distillation

High concentrations of alcohol are toxic to all living things, including the yeasts that produce it. Brewing yeasts can’t tolerate more than about 20%. So stronger drink can only be made by physically concentrating the alcohol in fermented liquids. The key to discovering distilled alcohol would have been two observations: that the vapors of a heated liquid can be recaptured by condensing them on a cool surface, and that the vapors of heated wine or beer are more strongly alcoholic than the original liquid.