What is distilling?

Sep 09, 2020

The science

Distilling is the process of separating the components of a liquid mixture by boiling it to produce vapour and then condensing the vapour and collecting it. It both a science and an art.

When we’re talking about whisky, distilling usually occurs in pot stills, and when the vapour condenses it will run from the still as a clear spirit called new make spirit (NMS). Distillers then collect NMS, reduce it to around 63% alcohol and age it in a barrel.

This might be an oversimplification because the art of creating a great spirit is a little more complex, with specific skills needed to produce an award-winning bottle of goodness.

The right raw ingredient

If you’re making a white spirit like gin from a sugar or grain base, brandy from a grape, or rum from a molasses– the process can be a little different (eg. possibly column stills) and we’re not even touching on other fermentable sources for alcohol.

As a distiller, the process of distillation commences right back at the raw ingredient. If we’re talking about whisky, then grain is the ingredient of choice and there is quite a process to produce the wort, which is then fermented to become wash (usually about 6% alcohol) and then transferred to the still to become spirit.

For whisky, the humble grain is typically first malted (by a maltster), then milled to ensure its starches (complex long chain molecules comprised of sugar molecules) are accessible, then a sugary wort is created by adding hot water to the milled grain and processing this for a time, before the liquid is drained off through the grain bed.

The process

At this stage, the production process is similar to that of making beer, and in fact breweries have been known to make the ‘wash’ for distilleries and hand it over to become a distilled spirit. In brewing, at this stage, you would boil the spirit and add hops for beer, but those steps are not required to make a distiller’s wash.

Once the ‘wort’ has been drained through the grain bed, it is then cooled and fermented – usually around 3-5 days but some distilleries will ferment for less and others for longer.

Once fermented, the wash (as it’s now known) is then transferred to the still and distilled twice (the wash run and the spirit run) to increase the volume of alcohol in the spirit. The final spirit (depending on the still you use and some other factors) will leave the still at around 70% alcohol (or ABV). The spirit is then watered down, and put into the barrels at 63% or thereabouts and left to rest until matured.

The technical systems

The technical components of distilling, including how to fill the still, what temperature to run it, how to do the cuts, how to test the spirit and all the other components of distillation is where the skilled art comes into play. This is also where courses like the Institute of Brewing and Distilling’s General Certificate can help, and where you need to gain experience and hands on learning.

But for now, that’s the quick overview of distilling. If you’re ready to start your own distillery then check out the course.

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