Pot stills versus column stills and the whisky each one makes

What a still does

Fermentation leaves a wash of around 8% ABV: water, alcohol and hundreds of flavour compounds. Alcohol boils at a lower temperature than water, so heating the wash sends a vapour richer in alcohol up the still. Cool that vapour and you collect a stronger liquid.

Every still also separates flavour compounds by how volatile they are. That is where the two designs part ways. Our guide to how whisky is made puts distillation in the context of the whole process.

The pot still: batch by batch

A pot still is a large copper kettle with a neck and a pipe called the lyne arm leading to a condenser. It is filled, heated, run and emptied, one batch at a time. Malt whisky is usually distilled twice. The first run in the wash still makes "low wines" of roughly 20 to 25% ABV. The second run in the spirit still makes the new make.

During the second run the distiller makes cuts. The first portion, the foreshots or heads, is rich in volatile compounds and is set aside. The middle cut, the heart, is kept as new make, typically around 65 to 72% ABV. The tail, called feints, is heavier and oily and also goes back for redistillation. Where those cut points sit is one of the biggest flavour decisions in a distillery.

Shape and copper change the spirit

Tall pot stills with long necks give more reflux: vapour condenses on the walls and falls back, so only the lighter compounds get through. That gives a lighter, fruitier spirit. Short, squat stills give a heavier, oilier one.

Copper matters as much as shape. It reacts with sulphur compounds produced by yeast and removes them. A slow, gentle run with plenty of copper contact gives a cleaner spirit. Rush it and the new make can smell meaty or rubbery. Our guide to getting new make spirit right covers cut points and copper contact in more depth.

The column still: continuous

A column still, also called a Coffey or patent still, is a tall cylinder divided by perforated plates. Wash goes in near the top, steam comes in at the bottom. On each plate the rising vapour strips alcohol from the falling liquid, so every plate works like a small distillation. It runs continuously for as long as wash and steam keep coming.

Columns can reach very high strength. Scotch grain whisky must be distilled below 94.8% ABV so that some character remains. Neutral spirit for vodka goes higher still. Columns are efficient and cheap to run per litre, which is why grain whisky and most Indian molasses spirit come from them.

Which whiskies come from which

• Single malt Scotch and Indian single malt: pot stills, usually double distilled.
• Irish pot still whiskey: pot stills, often triple distilled for a lighter spirit.
• Grain whisky: column stills, light and clean, the base of most blends.
• Bourbon: usually a column, called a beer still, followed by a doubler or thumper, a simple pot-type second stage. US rules cap distillation strength at 80% ABV, so bourbon keeps more grain character than Scotch grain whisky.

Hybrid stills, a pot with a short column of plates on top, are popular with craft distillers because one still can make gin, vodka and whisky.

Running costs and labour

A pot still uses a lot of energy for each litre of spirit, because every batch is heated from cold and run twice. It also needs a skilled operator for every spirit run, since the cuts are made by watching strength, temperature and aroma as the spirit flows from the spirit safe.

A column, once stable, runs for long periods with fewer interventions and much better energy use per litre. The trade is capital cost, height and the need for a steady supply of wash. For a small craft distillery making a few hundred litres of wash a day, a column often makes little economic sense on its own.

Choosing a still as a craft distiller

If whisky is the main goal, a pot still makes the richer spirit most drinkers expect from craft whisky. If you also need gin or vodka while the whisky ages, a hybrid gives flexibility at the cost of some complexity in operation.

Before buying, decide on the spirit you want to make and work backwards to the still. Size, heating method, copper surface and condenser type all change the new make. Changing them later is expensive.

Common questions

Is pot still whisky better than column still whisky?

Not better, different. Pot stills keep more flavour and body. Column stills make lighter, cleaner spirit efficiently, which suits grain whisky and blends.

Why are stills made of copper?

Copper removes sulphur compounds from the vapour and conducts heat well. Without it new make can smell of rubber or cooked vegetables.

What is a hybrid still?

A pot still with a column of plates above it. It can run as a simple pot or as a column, so one still can make whisky, gin and vodka.