Irish Whiskey’s Three Ingredients

October 31, 2021

by Mark McLaughlin

Irish Whiskey has gone through many iterations from the first mention of ‘aqua vitae’ – the water of life – in Ireland in the 1320s, when this precursor to the Irish whiskey we know today was more of an herb & spice infused spirit used mostly for medicinal purposes, although there may have been those who tested its recreational properties. It wasn’t until the first licenses to distill were granted from 1608 (in the area we now know as Bushmills) that whiskey began to resemble the spirit we know today.

Aqua Vitae translated to Irish, ‘as gaeilge’, became uisce beatha which in turn was shortened to fuisce, pronounced ‘fwish-ka’, with others referring to it as uisky, finally being anglicized to whiskey when our British overlords couldn’t wrap their tongues around our native language. And it was this Irish whiskey, more specifically Pot Still Irish Whiskey, that first gained global acclaim in the latter half of the 19th century by which time we had settled on our three main ingredients, water, grain & yeast.


When we consider the planning which the creators of Ireland’s great distilleries of the past would have done, and compare it with the planning of Ireland’s newest Irish whiskey distilleries, there is a common theme in their locations, their proximity to water.

When we consider the planning which the creators of Ireland’s great distilleries of the past would have done, and compare it with the planning of Ireland’s newest Irish Whiskey distilleries, there is a common theme in their locations, their proximity to water.

Whiskey distillery water wheel in Kilbeggan, Ireland.

Ireland’s oldest distillery, Kilbeggan Distillery, built in 1757, was built on the banks of the river Brosna, and was known as Locke’s Brusna Distillery for many years. And when it reopened in 2007, they began using water from that same source once again. Similarly, Bushmills, takes its water from the river Bush which runs through the distillery, and the Old Midleton distillery was conveniently built upon the Dungourney River, with the New Midleton distillery using this as one of its water sources.

Today, 2 forms of water are typically used in Irish whiskey distilleries:

Production Water:

The water used for production goes through 2 water treatment processes to ensure it is fit for consumption and will not have an adverse effect on the distillate:

  • Filtration: To remove any unwanted contaminants and/or suspended solids from the water. This should prevent the presence of any foul odours or tastes being present in the beer or distillate
  • Demineralisation: To remove or adjust the mineral levels of the water source in order to avoid any clumping or undesirable mineral salts making their way into your distillate.

Both processes are generally done through reverse osmosis, passing the water through a semi-permeable membrane, referred to as R.O. Water.

This water can then be used in processes such as, fermentation, distillation and for adjusting the A.B.V. of the distillate prior to filling casks, or before bottling.

Cooling Water:

This water does not have to be treated and can be constantly recycled throughout its journey around the distillery. The most common areas where cooling water is necessary are:

  • Brewhouse cooling, E.g. for adjusting the temperature of the wort prior to fermentation.
  • Stillhouse cooling. E.g. for cooling the condensers to convert the spirit back to liquid form during distillation.

This water can flow directly back to source prior to use in the distillery allowing distilleries to achieve zero waste with cooling water throughout the whiskey making process.

Many independent bottlers now also consider their water source for cutting their spirits’ A.B.V. prior to bottling, opting to use water from local rivers or springs, ensuring a connection with the area where their brands may be based, rather than where the spirit was distilled.


When considering pot distilled whiskeys, barley reigns supreme. Barley is a member of the grass family which grows in temperate climates throughout the world. It can be used in bread, soups, stews, and many more food varieties, although it is most commonly used for animal feed and secondary to that in the brewing and distilling industries.

The two-row spring barley generally used in whiskey production is traditionally sown in the spring and harvested in late August or early September, although there are many different varieties of barley being produced in Ireland globally in winter also. In the brewing and distilling industries, the type of barley is generally chosen for its yield per acre among other agronomic criteria.

The majority of barley used in the whiskey industry is ‘malted barley’, this means that the barley has been encouraged to grow, produce sugar, and then stopped growing through a process called malting. This process creates enzymes and exposes the starch which is necessary for brewing. Whether a distillery is using pot stills or column stills to produce spirit, malted barley must be used as the enzymes it contains are essential to converting the starch into alcohol.

For our famed Pot Still Irish Whiskey we see the use of unmalted barley and more recently we’ve seen the revival of many historical mash bills that include oats, wheat & rye, which we will explore in greater detail in upcoming member articles.

Maize (Corn) is commonly used in Grain Irish Whiskey, maize is a cereal, again part of the grass family, which has a high starch content, it’s like a little kernel of sugar. It grows significantly better in warmer climates, therefore a large amount of the corn used in the whiskey industry in Ireland is imported most specifically from the Bayonne in France, where Irish distillers source their corn from.

But with distilleries choosing to focus on Irish grown grains we are seeing some of the newer grain distilleries revert to using Irish wheat for their grain distillates. This move towards Irish grains is welcomed as there’s a significant amount of barley imported into Ireland as well, but with the rise in Irish distilleries there is also a questions whether the Irish grain farmers could keep up with the potential growth in Irish whiskey. This is a question we will certainly explore in future member articles.


Yeast, in its most basic description, is a fungus, and as with must fungi, it is present almost everywhere in the world. It joins the whiskey production process at the fermentation stage, where it is added to the wort in order to create alcohol. When yeast is added to a sugar-rich environment it consumes the sugar in order to multiply and through this function creates carbon dioxide(CO2) and alcohol.

The most common type of yeast used by distillers is Saccharomyces cerevisiae, known as distiller’s yeast, as its strength is metabolizing sugar and produces alcohol. It is bought in 25kg bags in a putty like form and is kept in refrigeration onsite. Then, before fermentation, the yeast goes through a ‘bubbing’ process where it is first creamed with water and then a small amount of wort or mash is added to it. This allows the yeast to propagate and adapt to the new environment, bringing it to an optimum level of efficiency before being added to the wort for fermentation. This process takes place in vessels known as bub tanks.

Some whiskey producers are experimenting with different varieties of yeast as opposed to just distillers yeast to see if they can create more desirable flavours in their distillates. In particular, Pearse Lyons distillery, founded by the late Dr. Pearse Lyons, are expected to do vast experimentation in yeast varieties, as parent company Alltech specialize in yeast products.

This should give you a basic understanding of Irish whiskeys’ 3 main ingredients and give you the basis to explore the three topics in greater depth as you continue to enjoy more Irish Whiskey stories & sips throughout your Irish whiskey journey.

XS <576px
SM ≥576px
MD ≥768px
LG ≥992px
XL ≥1200px