We spend all day every day finely crafting our Athrú single malt Irish whiskey, and that in itself is a complex process - without adding nomenclature into the mix. So here, we take a look at what defines a single malt whiskey - discover everything you need to know about the naming, making and legalities surrounding your favourite whiskey.

What is single malt whiskey?

A common misconception is that a bottle of single malt whiskey has all come from the same barrel or batch, but this isn’t the case. Most single malt whiskey will be a blend - which to add to further confusion, isn’t the same as a blended whiskey. A single malt will likely be a blend of whiskey from different casks and, possibly, different ages, but these are all from the same distillery. That’s because the ‘single’ in single malt means that all of the whiskey in the bottle has been produced by the same distillery.

As for the malt, this refers to the grain used in the whiskey, and to be a single malt whiskey, the grain must be one type - in Ireland, that’s barley, which has been malted. We use 100% malted barley in our single malt whiskey, currently sourced from 11 growers in Wexford, but we’ve also recently planted our own barley on-site here in the Hazelwood Estate.

Does single malt mean different things?

Yes and no. This is down to the governing laws in different countries and how they define their whiskeys. In Scotland, a single malt Scotch whisky has the same regulations as here in Ireland - the whiskey must be produced from one distillery and contain 100% malted barley, but these rules do vary from country to country. For example, in America some distilleries use the term single malt, but instead of using malted barley, they use rye. The grain used in a single malt must be 100% of the same grain, but it’s worth noting that this doesn’t have to come from the distillery itself, or even the same country as the whiskey is made. In Japan, the barley used in their whisky is often imported from the UK, but because the spirit is distilled and matured in Japan, it can still be classed as Japanese whisky.

Is single malt whiskey the same as single grain whiskey?

You’d be forgiven for thinking that the two are one and the same, but while single malt whiskey is a whiskey that’s all made at the same distillery and from the same grain (malted barley), single grain whiskey does all come from the same distillery, but the grain doesn’t have to be barley - corn, rye or wheat could be used in place of the barley, and the flavour profile would be different as a result. Single grain whiskeys are also typically produced using column, or Coffey, stills rather than pot stills which are used for making single malt whiskey.

What’s a single cask whiskey?

Whereas a single malt whiskey is a whiskey that’s made in the same distillery and from barley but can be made up from a number of casks, a single cask whiskey is one that’s made exclusively from one cask. These tend to be much rarer, and as a result, more expensive, because each cask will only yield a select number of bottles, usually 200-300.

A single malt whiskey will often be a blend of whiskeys from casks at the same distillery - when it comes to age statements on the bottle, the number reflects the youngest age of the whiskey inside - so if you buy a 12-year-old single malt, the youngest whiskey in the blend would be aged for 12 years, but this could be mixed with a 25-year-old whiskey from the same distillery.

A recent trend is for no age statement, so the bottle won’t say what age the whiskey is. Often, but not always, this indicates that the whiskey is relatively young. And, to further confuse matters, some distilleries, like Lough Gill, grow their own barley, and once a year, make a vary rare Single Estate Whiskey, where everything in the whiskey, from the water to the barley to the distillation and maturation is done in a single location/estate!

What’s the difference between single malt and blended whiskey?

Single malt whiskeys are blends in their own right, but they’re blended whiskeys from the same distillery. In Ireland, a blended whiskey can be one that’s made up of malt and grain whiskey, or a blend of single malt whiskeys from different distilleries - or a combination of both.

There are several reasons why a distiller may decide to blend their whiskey; it allows them to create an exact flavour profile by combining different whiskeys or grains, but it also helps to keep a whiskey consistent, which can be a significant factor if millions of bottles are being produced and exported each year.

What are the Irish whiskey regulations?

As you can see, the naming conventions for whiskey is just one part of the complexities. But there are also different regulations around the world around how different countries can make their whiskey. Some countries, like Ireland, Scotland and Japan all have similar regulations, whereas America have their own laws which differ significantly - their single malt whiskey must be 51% malted barley, unlike here where regulations stipulate that to be a single malt Irish whiskey, it must contain 100% malted barley.

The Irish Whiskey Act of 1980 states that Irish whiskey must:

Be made from a mash of malted barley, (other cereal grains optional)

Be mashed, fermented, distilled to no more than 94.8% ABV, and matured in wooden casks, such as oak, not exceeding 700 liters for a minimum of three years in the Republic of Ireland and/or Northern Ireland
Contain no additives other than water and caramel colouring
Retain the characteristics of its raw materials (i.e. the whiskey needs to taste and smell like the ingredients used to make it)
Be bottled at no less than 40% ABV.

Find out more about the Irish whiskey rules in our guide.

How We Make Our Single Malt Irish Whiskey The Athrú Way

We carefully craft our Athrú single malt whiskey using traditional techniques, but with some approaches unique to our Lough Gill Distillery. For example, the water we use during distillation and bottling comes from our own water source - beginning its life atop Benbulben and gently filtering down into the well right here on the Hazelwood Estate.

Our barley is grown for us by 11 growers in Wexford, and then malted for us by experts in Kildare, and once it arrives at our distillery, we store it in our silos, ready for it to continue its journey in becoming our single malt whiskey. The next step is distillation, and we do this three times in the Irish tradition, using our state-of-the-art pot stills.

The first part of the distillation process takes between 4 and 7 hours, and it’s where the fermented wash, or mash, is heated in the first still, which separates the alcohol to a strength of between 23 and 25% ABV. This liquid is the ‘low wines’, and we then take this and repeat the process in the next copper pot still, the feint still.

Once the feint still has done its job, we have a liquid called the feints, which is between 68-69% ABV. We then do the final part of the distillation - this liquid goes into our third copper pot still, known as the spirit still, and it’s distilled a third time.

The spirit leaves the spirit still at around 83% ABV, and it’s at this stage we add our water to it. This brings the ABV down to 63.5%, becoming cask strength Athrú whiskey.

During the distillation process, we only capture and cask a small portion of the distillate.

The fermented wort (wash) contains a broad range of different elements that evaporate at different temperatures. We split these elements into three groups, the foreshots (or head), potable spirit (the heart) and lastly the feints (the tail). The foreshots and feints are returned to the stills and it is only the distilled spirit captured in between these fractions which is casked. We do this to ensure we’re only capturing the best flavours and characteristics in our Athrú single malt.

Once our single malt whiskey has been distilled and we know it’s the best it can be, it’s stored in carefully selected ex-bourbon casks in our maturation warehouse - which is a massive six acres under roof. Here, the whiskey is matured and finished, and during its time resting here, it benefits from some unique elements, such as the fresh Atlantic air we’re blessed with here at Lough Gill.

Once the whiskey is fully matured, we bottle it, ready to be sipped and savoured by whiskey drinkers around the world.

Irish Single Malt Whiskey - What Is It?