Distillation Distilled

09th September 2021 / by Hannah Thaxter

Distillation of malt whisky is a complex process which involves all the senses. Hannah Thaxter spent a day with stillman Duncan MacFadyen (better known as Budgie) to discover some of the secrets of running the stills. Here's 5 things she found out.


It will be acetone at the start, says Budgie, like nail polish but when that smell goes it’s the end of the foreshot. After that it starts to get fruity smelling, then grassy, mossy and woody – there are 15 main types of smell – and by the end it’s an oak tannin smell, something I associate with warm wet trainers.

He demonstrates by showing me how to rub some of the spirit in my hands, letting the alcohol burn off and cupping my hands over my nose and mouth – sharp at the start, moving through florals and grasses and woodlands down to a whiff of wet leather – the sweaty but comforting shoe.

2/ As old as the stills

Bruichladdich’s oldest still dates from 1881 and still has its original bottom (although the seams have been coated with newer copper). It’s on a brick base – newer ones are on steel bases – and that’s because it was originally heated up by coal fire.

The wash stills have windows in, and spirit stills don’t – that’s because during distillation the liquor from the washbacks (which has yeast in) will make bubbles when it starts to warm up – you can see them through the glass and if they get too high you know to lower the temperature (slow the still down)

3/ Keeping a weather eye open

Time of year and time of day affects how things run.

Temperature is crucial. Spirit comes out at between 73% and 63% ABV at a temperature of between 17 and 23°C – but lots of things can affect how the still gets to that temperature. Sunlight can warm up the surface of the water being used for cooling for example, so you constantly have to adjust how you run the still – heating it up or cooling it down – throughout distillation.

4/ Essential oils

In each litre of spirit, 75% is alcohol, and 8-12% is fusel oils, and the rest is water. Without those oils the alcohol would simply evaporate! Fusel oils are longer chain (higher) alcohols than ethanol. They can be mildly toxic and in high concentrations have a nasty smell and taste (fusel is German for “bad liquor”). But in smaller concentrations they give whisky body and flavour.

If you run the still slowly (ie don’t boil it up and keep it boiling off the alcohol fast) you get fewer fusel oils. This trickle distillation is used for malt whisky – blended whisky generally contains more fusel oils.

You can tell how far along the distillation process the spirit is by taking some of the clear liquid from the spirit safe in a glass. Add the same amount of water and shake once. If you watch how the now cloudy liquid clears – the longer it takes the denser the oils and the nearer it is to being at the end of distillation.

5/ Under lock and key

There is only one key to the spirit safe lock – a large brass padlock.

When turned the mechanism pushes up metal spikes. The Excise man would have put a piece of paper over the spikes which would pierce the paper when he locked it – he would date and sign the paper. If anyone tampered with it, the spikes would move leaving telltale tears in the paper. A second man – a watcher – had to witness the opening and closing. This happened up to 1985.

Bruichladdich Distillery
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