How to Achieve High Purity in Alcohol Distillation
Common ingredients used in producing potable alcohol include corn, wheat, rye, malted barley, potatoes, sugar cane/molasses (rum) and agave (tequila/mezcal). Once these have been fermented, their ethanol must be further refined through distillation before consumption.
Distillation works by taking advantage of alcohol and water having different boiling points; alcohol evaporating more readily than water. By heating a wash or mash (beer) in an enclosed environment, alcohol can be separated from its liquid components – leaving only spent wash or mash behind which has cooled over time – leaving behind only collected vapors which are then redistillated to isolate only the molecules with lower boiling points like methanol and water which have higher boiling points (this process enables vodkas and whiskies to achieve such high purity levels.).
As part of this process, it is critical that the reflux ratio (how much of the vapor rises through the distillation column compared with what is collected as product) be maintained within acceptable levels for best purity and energy usage. This ratio dictates both level of purity and energy requirements.
At the end of distillation, the liquid that remains contains not only alcohol but also some water and chemical compounds called congeners which give spirit its characteristic flavour and aroma. As much of these congeners should be removed as possible to produce high quality spirits; many brands tout how many times their alcohol was distilled to demonstrate this quality. Advanced cocktail enthusiasts will recognize that even with simple distillation systems like this one in place, fractionating columns provide more surface area for the vapor/condensate mixture to come into contact and facilitate improved separation.