Today’s post, I have decided to bring out the effect of the boiling points of different liquids, more specifically of water and alcohol and how it impacts the production of spirits in the alcohol industry.

We all know different liquids convert into gas and start evaporating at different boiling points. In the case of water, the boiling point is 100 degree Celsius and this means that water will start boiling at this temperature. What happens if the temperature of a liquid is at subzero – Simple – the water freezes.

Now let us take the boiling the point of alcohol (ethanol – ethyl alcohol). Does it too start boiling at 100 deg Celsius or at higher or lower levels? The answer is alcohol has a lower boiling point and it means when heated, it reaches boiling point at 78.24 degree Celsius.

Similarly, boiling points of some of the other liquids are  – Ethyl acetate : 77.2, Acetaldehyde : 20.8, Acetone :56.08,  Alcohol – methyl (methyl alcohol, wood alcohol, wood naphtha or wood spirits) : 64.7, Ammonia at: – 35.5, Mercury at 356.9, Milk 100.5 and so on.

Now how does boiling point of liquid help the alcohol industry. Absolutely yes – it does so at the distillation stage of production of spirit.

A quick peep through the stages: Production of any grain spirit namely Whisky, Vodka, Gin,  involves mainly Milling, Mashing, Fermentation and then distillation followed by maturation or ageing process.

Milling is the process where the grain is milled to a rough flour called grist. The grist is added to a mash tun in the presence of hot water in order to get a porridge like substance which is then filtered to obtain what is called the wort, the sugary liquid. The sugary wort is then transferred to washback vessel for fermentation and yeast is added to convert the sugars into Co2 and alcohol. This liquid is the distiller’s beer or the wash with a strength ranging between 8% to 10 % of alcohol (ethanol = ethyl alcohol).

The beer or wash, which is a mix of alcohol and water, is then distilled. Distillation is the process that sets spirits apart from beer. To obtain this spirit, the wash(beer) is transferred to the column/pot copper still and heated. Since the boiling point of water is 100 degree Celsius and of ethanol 78.40 degree Celsius, the alcohol in the wash starts to boil first and converts into vapour. Along with-it other substances in the wash having lower and higher boiling points namely esters and heavy fusel oils also evaporate. On condensation the vapour cools and converts  to a distillate known as the low wines having a strength ranging between 21% to 24% alcohol by volume.

The low wines are collected in receiver and filled into the spirit copper pot still and heated. The spirit still has a bigger influence on the taste of the new make spirit. On heating the low wines, the volatile foreshots compounds evaporate first and are redirected for re-distillation with low wines. The middle cut is collected and the feints are again redistilled in the distillation run. The middle cut is collected is the new make spirit and has an alcohol by volume not greater than 80% in the case of whisky and can also touch 90 to 100 in the case of grain whisky and vodkas.

An example as to how the heating and the boiling point effects the volume of the wash(beer) vis a vis alcohol. A wash (beer) of 3000 litres which has a 10% alcohol by volume (300 litres)  volume significantly drops to around 1000 litres with 25% alcohol by volume (250 litres) of low wines after first distillation. So the boiling point of a liquid plays a key role in finally collecting the higher strength of alcohol.


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