Fermentation
Malted and Unmalted Barley
Irish whiskey is made using a mash bill of a mix of malted and unmalted Barley which is sourced predominantly from farms within the Munster region surrounding our distillery. Midleton distillery is one of the few in the world that uses unmalted barley. That wasn’t always the case though as this is the traditional way of making Irish whiskey since the 1800s. The English Malt tax is widely given as the reason for using unmalted barley as it made whiskey production cheaper but it does impart a silky or creamy mouthfeel to the whiskey that is difficult to achieve from malted barley. It also adds a spiciness that really marks out Irish whiskey. That’s not to diminish the role of malted barley which is crucial to whiskey production. Visually, it is almost identical to unmalted barley but when placed between your teeth, it is crunchy and sweet to taste. The primary reason for malting barley is to make the starch accessible to the yeast during the fermentation stage. Of course, the tradition in many countries, most notably Scotland, is to make whiskey from 100% malted barley which imparts a particularly malty, biscuity or cereal character. The process of malting barley takes about four days. The barley is encouraged to grow, to stimulate enzymes which break down the cell walls which contain starch. This is done through steeping the barley in water for a number of hours to trick it into germinating. It is then laid out on mats at a temperature of 18 degrees Celsius and the barley starts to sprout. Once germination has reached a certain point, the malter will kiln dry the barley, in closed smokeless kilns to ‘fix’ the enzymes ready for their conversion to sugars in the fermentation stage.
Water
The soft, clear water, used by the distillers at Midleton Distillery, is sourced from the Dungourney River. This reliable river rises in the lush green hills of neighbouring Clonmult, and flows through a deep glen as it makes its way to the sea at the nearby village of Ballinacurra, one mile outside Midleton town. The existence of this river was one of the critical factors that led to the location of the distillery in Midleton. Another unique feature of the Distillery site in Midleton, is the fact that it sits above a vast underground cavernous limestone system. The abundance of caves ensure abundant supplies of cool underground ‘cavern’ water from which the distiller can draw as necessary.
Milling, Mashing & Fermentation
The first stage of whiskey production involves the creation of a beer which is then distilled in our copper pot still to make our distillate. Milling – Different proportions of unmalted and malted barley are milled into a coarse flour called ‘grist’ which is then sent forward for mashing. Mashing – Hot water added to the grist, now called mash, which is mixed. This lasts approximately 2 hours, allowing the starch to be made available for conversion to fermentable sugars. The mash is then drained in the Lauter Tun and the liquid extract, called wort, is now sent to fermentation. Fermentation – The wort is pumped into a large vessel called a washback, into which liquid yeast is added which consumes the sugar producing alcohol and carbon dioxide. The resulting liquid is called wash and has an alcohol level of about 10% vol and is effectively a type of beer.
Distillation
Triple Distillation
The first distillation takes place in the wash still, into which the wash is added and heat is applied. As alcohol boils at 78.1oC, its vapours are the first to rise from the wash and depart upwards through the neck of the still. Copper piping leads from the neck of the still to a horizontal condenser where the vapours are converted back into a liquid; this is the first of the spirit and it has an alcohol volume of approximately 40%. The spirit captured from the wash still (now known as low wines), is now fed into the second or feints still. Here the spirit captured has an alcohol volume of approximately 70%. Finally, and almost unique to Ireland, the feints are fed into the third or spirits still. The spirit is filled into oak casks for maturation and now has an alcohol strength of 85% vol.
Distillate Heads/Tails
Throughout the entire distillation, the master distiller at Midleton Distillery, Brian Nation, will carefully control every step of the process. The first alcohols and flavour compounds to come from the stills are very high in esters which contribute to the fragrant, floral and spicy characteristics of a spirit. However the first runnings, known as ‘heads’ or ‘fore-shots’, are too high in concentration to be enjoyed and also contain fusel oils and esters left behind from the previous distillation. The distiller monitors the heads, deciding when he can make a cut and start collecting the ‘heart’ or ‘middle cut’ of each distillation. Similarly with the ‘tails’ there comes a point when the balance tips towards undesirable flavours again. The distiller will monitor the hearts to decide when to redirect the tails. Heads and tails are reused in subsequent distillations to ensure that nothing goes to waste.
Why copper is used
Copper plays a vital role in pot still distillation apart from its excellent heat conduction. The production of esters in distillation can include highly volatile and pungent sulphur compounds that are undesirable. The copper has a chemical reaction with sulphur to form copper sulfate which remains behind in the still. The longer the contact time between the spirit and the copper, the lighter the spirit will be in style.
Still shape and design
Hand made, copper pot stills are crucial to the distillation process. Pot stills can can vary in style and shape – onion-shaped, conical, ball and lantern – resulting in different styles of distillate as the shape and style of the still will vary where the distillate condenses. As the vapours rise up the neck of the pot still and the temperatures gradually decrease, the less volatile components will condense and fall back into the pot, this is referred to as reflux. These tend to be the heavier congeners resulting in a lighter style and higher strength spirit as the lighter components are better able to escape into the neck. The head of the still is attached to the pot and again varies in size and shape – tapered, straight-sided, short or long. The lyne arm connects to the head via the swan neck and this leads to the shell and tube condenser where the vapour is converted back into liquid form. In Midleton we have the largest pot stills in the world in operation with three full sets of three copper pot stills as of 2017. Our garden Stillhouse now holds two full sets allowing our Master Distiller to create different styles and types of distillate depending on what brand he is distilling for.
Maturation
Sherry Barrel Vs Bourbon Barrel
Our large sherry casks, all manufactured by hand at Jerez de la Frontera, Spain, are made from European oak, Quercus robur, and have a typical capacity of 500 litres. The butts used to mature whiskeys at Midleton are constructed specially for us using strict guidelines. Prior to being ‘shipped home’, the butts will have held sherry wine for two years. Extreme care is taken to avoid any potential for sulphur taint and there is absolutely no use of sulphur candles in the handling of Midleton Distillery owned and bound butts. Bourbon Barrels are made from American white oak, Quercus alba, and have a typical capacity of 200 litres. Many of these barrels are manufactured in the state of Kentucky, and have held Bourbon whiskey for a period of 3 or 4 years prior to being shipped to Ireland. Only 1st quality seasoned casks are purchased for use at the Midleton distillery.
Role of Master of Maturation – Kevin O’Gorman
The role of the master of maturation covers a very many key elements, from the sourcing of the wood, to the sampling, to the crucial decision as to when a whiskey is ready to be woken up. It is during these long sleeps that our barrels, our ex bourbon and ex sherry casks, impart their distinctive flavours, colours and aromas. While our whiskey for Redbreast 12 is aged for a minimum of 12 years, it is often made up of whiskeys that are many, many years older. And, as for our older Redbreast expressions, they, just like people, tend to mellow more with age.
The story of Sherry influence
The sherry influence in Redbreast is a story of craftsmen separated by almost 2000 miles from Jerez to Cork but drawn together by their shared passions, passed down from generation to generation. Beginning in the forests of Galicia, north-west Spain, 150 year old oak trees are felled, sawn and seasoned. Next the coopers in the Antonio Páez Lobato Bodega craft the oak into casks, which are then seasoned with Oloroso sherry for 2 years in the finest Bodegas in nearby Jerez. The sherry is then decanted and the butts are transported by boat to the Midleton Distillery, to be filled with new-make Single Pot Still Irish whiskey. Once filled they go for a long sleep in our Midleton warehouses where time works its magic to produce Redbreast. Join Head Blender Billy Leighton as he takes us on the journey of the sherry butt from forest to warehouse.
Difference between sherry finished and sherry matured
An interesting side note on the maturation of whiskey is cask maturation versus cask finishing. For example our Birdhouse special edition bottling – Mano a Lamh was a cask matured whiskey and our Redbreast Lustau sherry finished edition is just that, finished in a sherry cask. Sherry matured refers to the whiskey spending its entire life in a sherry butt. This results in a full flavoured whiskey, showing the strong influence of sherry in the final whiskey. By contrast sherry finished means that the final liquid has spent a final period of maturation solely in a sherry butt. Redbreast Lustau edition is initially matured in traditional bourbon and sherry barrels for a period of 9-12 years. It is then finished in first fill sherry butts for 1 additional year in first fill hand selected sherry butts.
Blending and bottling
Bourbon Flavour Profile
They say that travel broadens the mind, and well it certainly broadens one’s flavour profile. Our American barrels from Kentucky and Tennessee bring a whole array of flavours to our Redbreast family. The charred inner linings of these casks allow our whiskey to seep in during maturation, and when it withdraws in the cooler winter months our whiskey takes with it the spectrum of bourbon flavours hidden within, from the vanilla to the nutmeg and cinnamon. Join Billy as he dissects the flavour profile he is looking for from these barrels in this short video.
The art of the blender
As Head Blender, it is my responsibility to discern and pluck the individual flavours and iconic tastes of Redbreast from the dizzying array of whiskeys that have matured in its honour. Only by following in the footsteps of legendary blenders, and by following my own nose, can I blend all the whiskeys, cask types, distillate types and flavours to form the exact notes, colours and aromas of each Redbreast. And while the five permanent members of the Redbreast family all share the same DNA, each one has their own very unique and distinct characteristics – or personalities.
Sherry Flavour Profile
The sherry flavour profile of our Redbreast whiskey is perhaps the most beloved part of our whiskey for many of our loyal followers. The deep flavour, originating in the finest bodegas, is an iconic feature of our Redbreast and creates a complex flavour profile that is fun to simply sit back and dissect all the different strands of Sherry, its notes and hidden flavours. Join Billy as he dissects the flavour profile he is looking for in this short video.