Nephin Whiskey

The way Irish Whiskey used to be.


The basic process for making whiskey hasn’t changed in hundreds of years, but the devil is in the detail.

The Making of Whiskey

The basic process for making whiskey hasn’t changed in hundreds of years but the variations on the basic process make all the difference to the quality, flavor and authenticity of the spirit.  

The entire process from start to finish takes several years when barley growing time and maturation time is counted.  Nephin Whiskey is involved in every aspect from planting the barley with the local farmers to handcrafting the casks we are using, so it takes us even longer than other distilleries.  Luckily, the pace of Lahardaun village life suits long, slow processes and so we can give the time and respect each small step requires to fulfill the Nephin vision.

Firstly a type of grain must be selected.  Most American whiskeys use corn (also called maize) or rye or a mixture of several different grains.  Malt whiskeys use only malted barley.

A blended whiskey, mixes a small amount of malt whiskey with a large amount of cheaper grain whiskey.  The intertwined history of the Irish & Scottish malts and blends is absolutely fascinating.

Grain whiskey is generally made in large, efficient column stills which run continuously often for a year at a time.  Whiskey made in pot still is made one batch at a time and that is the process we are following for this overview.



There are thousands of different varieties of barley, so selecting the variety of barley seed is the first step.  Two major groups are Spring barley and Winter barley and their name suggests the time of year which they are planted.  Winter barley needs low temperatures to flower whereas Spring barley has much lower cold weather tolerance.  Barley varieties used for distillation are almost exclusively Spring barley. Growing conditions in the West of Ireland are excellent due to the relatively mild temperatures and abundant rain even during the Summer. 

Fields in the shadow of Nephin mountain are ploughed in early Spring, ready for Nephin Whiskey barley planting.

Fields in the shadow of Nephin mountain are ploughed in early Spring, ready for Nephin Whiskey barley planting.


Harvesting is simply the cutting of the barley and the separation of the straw from the grain.  The grain is taken away to be dried, as reducing the moisture content to about 12% allows it to be stored over winter.  The straw is saved and used for animal feed, bedding or in the special case of Nephin Limited Edition Box it’s used as a natural packing material.

Nephin Whiskey barley almost ready for harvesting in Autumn.

Nephin Whiskey barley almost ready for harvesting in Autumn.


Malting is a process whereby dry, harvested barley is soaked in water, often called ‘steeping’ or ‘wetting’. Left for a few days, the grain starts to come alive (germinate) and produces a shoot.  This process is stopped at the exact time by drying it in a kiln, which is essentially a large oven.  Peated malt whiskey allows smoke from turf (which is simply another name for peat) to billow through the barley during this process.  This cycle from steeping, germinating and kilning usually takes between one and two weeks.

During the germination phase the barley has naturally made it’s starch content available by breaking down the protein surrounding the starch and has started to convert the starch to sugars.


Milling is a very simple process which grinds the malt into fine particles so that the center is accessible.  After milling the malt has been transformed to grist, containing flour, grits and husk.  The husk is the outer “shell” of the barley and can be seen in the grist as an empty container.


As mentioned above, the process of converting the starch to sugars has already started during the germination phase of malting but was stopped by kilning.  This conversion is now restarted by adding hot water (usually 60 - 65 degrees Celsius) to the grist in the mashing vessel.  The liquid drained from this vessel is called the "wort" and the bulk left behind is "spent grain".  Nephin have teamed up with local farmers who use this spent grain as a natural, high protein animal feed so that there are no waste products.


The wort is now transferred to large fermentation vessels known as washbacks and a quantity of yeast is added.  There are many different strains of yeast and the distiller's choice of yeast will have a significant impact on the character of the final spirit.   The quantity of yeast added is calculated depending on the volume of wort in the tank and is called the inoculum.  The yeast will multiply during the course of the fermentation and each new yeast cell will convert the sugars present in the wort into alcohol. 

The temperature in the washbacks is controlled by the distiller.  If the temperatures are low, significantly less alcohol will be produced giving a low 'yield' but temperatures above about 38C are harmful to yeast and the cells will start to die off.   The yeast itself produces heat as it converts the sugars to alcohol.

Esters produced during fermentation give the complex flavors which the whiskey lovers will later savor.

Typical fermentation times are 2 -3 days for this process from start to finish.  The fermented liquid is now called the wash and is transferred to the wash still to begin distillation.    


Distillation is fundamentally the separation of alcohol from water by taking advantage of the fact that water has a higher boiling point.  So if the mixture is heated to lower than 100 C but above 78.5 C, then theoretically the alcohol will evaporate and the water will get left behind.  

This process was traditionally carried out in a copper pot still, which is the classic shape that most people expect whiskey to be made in.  However from 1830 onwards column stills or continuous stills were introduced which are more efficient (and therefore cheaper) methods of achieving distillation.  Pot stills typically create lower alcohol distillates and more flavorful spirits than columns still.  Blended whiskey producers tend to produce their grain whiskey in tall continuous stills and blend with a small amount of malt whiskey made in pot stills.  

The use of copper as a material for pot stills is important.  The copper creates 'fruitiness' in the spirit and reacts with pungent sulphur compounds to remove them.  Nowadays there are a range of "pot stills" which use cheaper metals for the bulk of the still and add a small part of copper at the top but you can always tell by visiting the distillery and checking if the stills are all copper or a mix of metals.  There are also "hybrid stills" which mix elements of pot stills with column distillation which traditional whiskey lovers have to watch out for.


The distilled spirit, sometimes called 'new make' is transferred into wooden casks for aging.  Irish whiskey (like it's Scotch cousin) must be stored for 3 years in these casks before it is legally allowed to be Irish whiskey.  You can read about the fascinating history and variety of casks

The choice of casks has a dramatic influence on the final spirit.  The vast majority of Irish whiskey is aged in casks which have been used once for bourbon maturation and then imported to Ireland from the US.  The use of casks which have been used several times for sherry, port, sweet wines or other flavorsome spirits will transfer some of those notes to the final spirit.  The size of the cask has a direct influence on the maturation of the whiskey.  A smaller cask has a higher surface area of wood in contact per liter of spirit, so will mature the spirit more in a given time period.  This is why knowing the 'age' of a whiskey in years is not a reliable indication of it's maturity.


Once the spirit has been matured the blender chooses a selection of casks to be blended.  If making blended whiskey this step will involve mixing different types of whiskey - large amounts of cheap grain whiskey with a small amount of malt whiskey.  If making malt whiskey the blending simply involves mixing the contents of different casks of malt whiskey together.  

Once the spirit has been blended in a vat, the alcohol strength of the final product is achieved by adding water.  Typically a malt whiskey will be close to 60% alcohol while in the cask.  If the desired bottle strength is 40% (which is common for cheaper whiskeys) then 1 Liter of water will be added for every 2 Liters of the spirit in the vat.

Bottling at 40% ( which is 80 proof) is attractive to accountants, however once water is then added by the consumer to the whiskey , some of the very flavorsome ester molecules attach to the water molecules and give a cloudy appearance. There are two solutions to this. One is to chill filter the whiskey. This removes the potential for a hazy appearance but it also removes those very desirable ester flavors. Nephin want to retain such flavors and so have opted to upset the accountants and bottle at a higher alcohol strength of 46% (92 proof). 

Chill filtering is the process of chilling whiskey to a low temperature so that some natural fatty acids, proteins and esters become solid and are easily removed by draining the remaining liquid.  The problem with this process is that the natural esters that are being removed are exactly the part that is giving the taste!  So you've whiskey which you can bottle at 40% and that won't go 'cloudy' if you add water but you've removed a bunch of the nice flavors.  Many blended whiskeys are tasteless enough to start with, so perhaps this doesn't matter for some.

Next the bottler must choose what additives to use.  Nephin Whiskey are adamantly against the use of all additives and will never add anything to our Whiskey.  E150 is a caramel coloring that is commonly used and gives the whiskey a darker color.  Again the marketing departments are largely responsible for this "innovation", reasoning that if the color is darker, customers may think it's older and may associate age with quality and therefore think they're getting a better whiskey for a cheaper price.  

The whiskey is now ready for bottling and so is either branded by the distillery itself, or is bottled under a different label.  Many "brands" of whiskey are simply spirits purchased from the same distillery and labelled differently.

Nephin Whiskey will always be made in Nephin Distillery which is at the foot of Nephin mountain.  This authenticity is important to us and is the first thing we check when buying other bottles of single malts for our own enjoyment.

Hope you enjoyed the overview of the whiskey making process.  We hope you'll come visit Nephin distillery once completed where we can show you the above process in real life.  Meantime, you can get yourself one of the first collector edition numbered bottles of Nephin Whiskey or for further learning, we've put together a glossary of technical terms used in whiskey making.

(c) Nephin Whiskey Company Ltd.  Nephin is a registered trademark of Nephin Whiskey Company.