Distillery-produced ethanol fuels vehicles as well as being used in products like hand sanitisers which have proven popular during the COVID-19 pandemic. Ethanol often replaces fossil fuels to reduce carbon footprint and dependence on foreign oil sources.
Distillation process consumes an enormous amount of energy; at normal atmospheric pressure it takes approximately 15,000 BTU/pound of ethanol produced to evaporate and condense water/alcohol from liquid to vapor state compared with 11,500 BTU/pound for combustion of fossil fuels.
Lower pressures cause the azeotrope to dissipate, allowing alcohol concentration in vapor to move towards 100 percent more quickly; however, this requires extremely high reflux ratios, increasing energy expenditure required to evaporate and condense vapors so only fractions desired for collection can be extracted.
First to evaporate are those containing less-than-desirable and sometimes harmful congeners (known as heads). These can be separated out by diverting spirit flowing from the condenser, leaving only more desirable ethanol (known as heart) which will then be saved and bottled. Timing this transition between heads and hearts requires master distillers with great skill – getting it wrong could result in subpar spirits while cutting too early can result in wasted ethanol and money.