Production Process
At
Cooley Distillery we distil malt whiskey (made up of 100% malted barley, water
and yeast) and grain whiskey (made up of maize, malted barley, water and yeast).
A single malt comes from one distillery while a blended whiskey is a combination
of malt and grain whiskey.
Cooley Irish whiskies are distilled in copper pot stills (malts) and patent stills.
Malt Whiskey
Malting:
Barley is first steeped in water to germinate. Starches in the sprouting grains
are gradually converted into natural sugars. After 7 - 14 days green malt goes
to kiln for drying. The heat halts the growth, and the barley is then ready
for mashing.
Mashing: The dried malt is ground into coarse flour or grist, which is mixed with hot water as it pours into the mash tun. After mashing, the sweet sugary liquid is known as wort.
Fermentation: Yeast is added to the wort and fermentation begins. The living yeast feeds on sugars, producing ethanol and other alcohols. Large volumes of carbon dioxide gas are also produced and the wash froths violently. After about 2 days, fermentation dies down and the wash contains about 8% of alcohol by volume.
Distillation:
The wash is distilled twice, first in a wash still to separate the alcohol from
water, yeast and other waste matter. The distillate from the wash still known
as low wines then goes to a spirit still. The more volatile compounds are distilled
off first. Then only pure cut or the heart of the run, which is about 66 % alcohol
by volume, is collected in the spirits receiver. And the more oily compounds
are then collected separately at the end of the distillation.
Malt Whiskey Distillation
In distillation, the still is heated to just below the boiling point of water and the alcohol and other compounds with a lower boiling point vaporise first and pass over the neck into either a condenser or a worm - a large copper coil immersed in cold running water.
The shape and size of the pot stills affect the character of the individual whiskey.
Smaller stills with larger necks produce more refined whiskies as in the case of Cooley whiskies.
The manner in which the stills are run also affects the quality of the final product.
Cooley distils spirit in the stills 50% longer than the practise elsewhere.
Grain Whiskey Distillation in Columns
Mashing: Firstly, the maize grain is milled into a flour. Water is then mixed into the flour to make a slurry. It is then pumped through a pipe and heated to 155 C for half an hour. The slurry is then cooled and the malted barley is added (about 10-12% of quantity of maize).
Fermentation: Once the malt is added, the sugary liquid or wort is cooled and put into the fermentation tanks for a minimum of 48 hours.
Distillation: After fermentation, two separate distillation columns are used to produce a spirit of 94.6% alcohol which has the exact balance to produce one of the most flavoursome of grain whiskies.
Maturing
After
distillation tankers take all new spirit from the distillery in Cooley to the
old Locke's distillery in Kilbeggan, Co. Westmeath. This is where the warehousing,
filling and coopering facilities for all Cooley whiskies take place.
The spirit is placed into oak barrels, the majority of which are vanilla-rich first-fill ex-Bourbon barrels, used in some cases up to three times for maturation.
It is during maturation that the whiskey becomes smoother, more flavoursome, and draws its golden colour from the cask. A proportion of higher alcohols turn into esters and other complex compounds, which subtly enhance each whiskey's distinctive characteristics. About 2% of whiskey evaporates from the cask each year - the angel's share.
Whiskies are aged for a minimum of 3 but usually 5 years in the 200 year old stone warehouses at John Locke's. These warehouses are cool, moist and dark and ultimately produce a different whiskey than whiskey which is matured in a concrete modern structure.
Each barrel is specially numbered according to the production year, the contents of the barrels being either malt or grain whiskey along with their respective batch numbers, the number of the malt barrels and grain barrels themselves, and finally the litre quantity.
The
master blender from Cooley, carefully selects the casks of whiskies to ensure
that the final product is well balanced, smooth and unique. Cooley produces
flavoursome whiskies which are generally sweet, smooth and mature more smoothly
than most whiskies.
All Cooley whiskies are chill filtered before bottling except for Connemara Cask Strength. The purpose of chill filtration is to increase the clarity of the whiskey by removing compounds such as charcoal, pieces of wood and fatty acids which tend to cause cloudiness.
Once bottled,whiskey does not mature further. Whiskey must be a minimum of 40% alcohol by volume, this is the European standard but whiskey can be up to "cask strength" of about 60%.
As a result of the attention to detail of the traditional process of making whiskey, Cooley distilleries produce outstanding and award winning whiskies enjoyed the world over
