Single pot still Irish whiskey

A style defined by its grain bill

Single pot still Irish whiskey is made at a single distillery from a mash that contains both malted and unmalted barley, distilled in pot stills. The Irish whiskey technical file sets the recipe: at least 30% malted barley, at least 30% unmalted barley and up to 5% of other unmalted cereals such as oats or rye.

That unmalted barley is the signature. It brings a thick, oily, creamy texture and a peppery spice that malt whisky made only from malted barley does not have. Our guide to the rules that define Irish whiskey covers the other three Irish categories.

Why unmalted barley

The use of raw barley is commonly traced back to taxes on malt in eighteenth and nineteenth century Ireland. Using unmalted grain reduced the amount of taxed malt in each mash. Whatever the full story, distillers found the resulting whiskey had a character worth keeping and it became the classic Irish style of the nineteenth century.

Raw barley is harder to work with than malt. It has no enzymes of its own and its starch is tougher, so the malted barley in the mash has to do the converting. Distillers grind it finely and manage the mash carefully. The extra effort shows in the glass.

Pot stills and triple distillation

All single pot still whiskey is distilled in copper pot stills. Many Irish distillers triple distil, running the spirit through three stills rather than the two common in Scotland. Triple distillation tends to produce a lighter, cleaner spirit with a higher strength off the final still, though the style of the stills and the cut points matter just as much.

Our guide to pot still shape and reflux explains why the size and shape of the copper changes the spirit. A tall still with a long neck gives more copper contact and a lighter result. A short squat still gives a heavier, oilier spirit.

Ageing and the rules

Like all Irish whiskey, single pot still must mature for at least three years in wooden casks on the island of Ireland and be bottled at a minimum of 40% ABV. Distillers use ex-bourbon casks for vanilla and coconut, sherry casks for dried fruit and nuts and a range of wine and other casks for finishing.

Single pot still is a protected category. The words on the label tell you the grain bill, the still type and that it all came from one distillery. That is a lot of information in three words.

What it tastes like

The texture is the first thing most people notice. Single pot still feels thick and creamy in the mouth, almost oily. The flavours that follow often include:

• green apple, pear and orchard fruit
• black pepper, clove and a gentle spiciness from the raw barley
• honey, vanilla and toasted oak from the cask
• dried fruit and nuttiness when sherry casks are used

Taste it beside a blended Irish whiskey and the difference in body is obvious within seconds.

Pot still against the other Irish styles

Irish whiskey has four legal categories and it helps to see where single pot still sits:

• Single malt: 100% malted barley, pot stills, one distillery.
• Single pot still: malted and unmalted barley, pot stills, one distillery.
• Grain: usually maize or wheat with some malted barley, column stills.
• Blended: a mix of two or more of the above.

Most Irish whiskey sold around the world is blended, built on light grain whiskey. Single pot still is a smaller category and a more distinctive one. If a blended Irish whiskey tastes a little creamy and spicy, there is a good chance some pot still whiskey is in the mix.

For a taster, the pot still category is the clearest lesson in how a grain bill changes flavour. Same barley, same island, same kind of still. The only big change is that some of the barley was never malted.

How to taste it well

Pour 25 ml into a tulip glass and give it a minute. Nose it gently, since the spirit is often lively. Taste a small sip neat, then add a few drops of water and taste again. Water often opens up the fruit and calms the pepper. Drink a glass of water alongside, keep pours small and arrange a ride home if you are tasting out.

Your first step: next time you see an Irish whiskey on a menu, check whether it says single pot still. If it does, order it neat with water on the side and pay attention to the texture before anything else.

Common questions

What is single pot still Irish whiskey?

Irish whiskey made at one distillery from a mash of malted and unmalted barley, distilled in copper pot stills.

How much unmalted barley is in single pot still?

The technical file requires at least 30% malted barley and at least 30% unmalted barley, with up to 5% other unmalted cereals.

Is single pot still always triple distilled?

Not always. Triple distillation is common in Ireland, but the category is defined by its grain bill and pot stills.