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Why do you distil alcohol?

In this post, we explore why you distil alcohol and how spirits in general are made.

What is the purpose of distilling alcohol?

When we think about how our favourite spirits are made, many of us have vague notions of processes like fermentation and distillation taking place in a distillery. You may even have visited a distillery and seen such spirits being produced. But what is distilling exactly, and why do we need to distil alcohol?

In short, distillation is the process of heating a liquid to separate it into its individual liquid parts – water and alcohol. Different liquids have different boiling points, and it’s by vaporising these liquids that we achieve the separation we need for making spirits. Pure alcohol vaporises at 78.4°C, while you’ll know that for water, it’s 100°C. The vapours produced during distillation are separated, condensed and collected for use in making spirits. 

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Why do we distil alcohol?

Glad you asked! There are 3 reasons:

  1. To extract part of the alcoholic liquid – the all-important ethanol that makes your beverage an alcoholic one!
  2. By doing this, the ethanol becomes much more concentrated. Usually the ethanol level goes from 10% to around 75% through distilling. It’s this pure and concentrated alcohol we want to use to make a clean, beautiful-tasting spirit.
  3. The distillation process also extracts what are called ‘congeners’ – natural compounds, or flavour notes, that occur as a result of the distilling process. Of those that are desirable, they add to the character and overall flavour and aroma profile of the finished drink.

When you distil alcohol it is a meticulous process that transforms fermented products into pure, concentrated ethanol for crafting fine spirits.

How are spirits made?

Raw materials

Raw materials for spirits are in the form of a starchy or sugary crop. Crops commonly used range from potatoes to cereal grains such as wheat, rye or barley, and often sugar cane or grapes. These are turned into a sugary liquid. The distiller will bear in mind that the crop they use will contribute flavour (those congeners!) to the finished drink, so choice and quality are important.

Barley for distilling

Fermentation

Yeast is added to this sugary liquid. Being a live culture, the yeast then feeds on all that sugar and in doing so, produces alcohols, congeners (including a type called ‘esters’ which have a fruity scent!) and a waste product – CO2. Once the yeast has turned all of that sugar into alcohol, the fermentation stage is complete and we’re left with an alcoholic liquid called mash that is around 10% ABV.

Distillation

Now it’s time to extract the ethanol from the other alcohols and the water in the liquid that was produced during fermentation.

Distillation happens in apparatus called stills (which take their name from distillation!) – chambers with a vessel to collect the purified alcohol. The designs of still vary, but they are all heated by steam, and many have viewing windows so the process can be monitored.

In a column still – a type which allows the ABV of the alcohol to climb as high as 96% – a distillation takes place on each plate (think of these as sitting like dinner plates in a stack, within the tall, cylindrical column). A constant supply of ethanol goes into the still, which is then continually concentrated and removed from the still.

Back to those congeners! While the ethanol extraction and concentration process is going on, those congeners are being separated out throughout the height of the still, and the most volatile ones, with the lowest boiling point, will vaporise first and reach the top (known as the ‘heads’, or ‘foreshots’), and the least volatile will be continuously drawn off from the bottom (the ‘tails’ or ‘faints’).

The desirable ethanol we’re after during this process is described as the ‘heart’, and this is diverted and saved, ready for use later. Part of the art of being a distiller is knowing when to cut this outflow between the heads to hearts and the hearts to tail without losing precious ethanol! The point at which the heart is drawn off will dictate the level of congeners and depend on whether you are creating a spirit such as rum or a spirit with such a high ABV that the spirit is neutral – often used in culinary or medical applications. Fun fact: it’s a column still’s ability to reach these high ABVs that mean this is the still type used to make vodka.

Refining and ageing

Post-distillation, it’s time to cool everything down, and at this point, aromas may be added or refined, as well as any colourants, and sugar and water.

Spirits such as whiskey that are going for oak maturation will go into barrels at this point. Others are stored in glass vessels called demijohns to stop further oxidation until they are ready to go to the next stage.

An exciting step is when any flavours are added, and these might be natural, such as fruits or botanicals, or artificial. This can be done via maceration – where the flavouring is added to ‘steep’ in the alcohol – or via re-distillation.

For a great many spirits, the finished flavours come from blending spirits together that have all been distilled and matured in various ways. This opens up a wealth of opportunities for complex flavours, strengths and delectable characteristics.

Finishing

By this time, the spirit has been on quite a journey! The last stage of production is finishing, where final adjustments might be made, including filtration. After that, the spirit is ready for bottling and labelling.

Why do you distil gin?

Earlier, we mentioned neutral alcohol, and it’s this which makes gin, with botanicals added for flavour and character. Most gin distilleries use a third-party neutral spirit made from grain, known as Neutral Grain Spirit (NGS). Some are made from molasses or grapes.

Distilling Grapes for Gin

Gins can be re-distilled, which is also known as ‘rectification’, which can remove any impurities and add flavour to the gin via a selection of botanicals. Again, the skill lies here in the aromas coming out of the still telling the distiller it’s time to run off that pure ‘hearts’ cut.

All in all, the art of distillation is a clever blend of science, skill and tradition, too – it’s thought that alcohol was first distilled as far back as the 12th century! While a distiller will often use state-of-the-art equipment, the process of distilling hasn’t much altered through the ages.

If you would like more insight into how to produce your own branded spirits… without having to start your own distillery and learn your heads from your tails, have a browse of our distilling services page.

Interested in crafting your own bespoke spirits without the hassle?

Explore our Contract Distilling service! Let us take your vision from concept to bottle with the expertise and precision of our distillation process. Whether you’re looking to create a signature gin, or any spirit in between, we’re here to bring your unique creation to life. Dive into the world of distillation with us and distil your brand’s essence into a bottle. Get in touch to learn more and start your distilling journey today!