[7] It is believed that Irish monks brought the technique of distilling perfumes back to Ireland from their travels to southern Europe around 1,000 AD.

[7] The oldest known documented record of whiskey in Ireland was in 1405; in the Annals of Clonmacnoise it was written that the head of a clan died after "taking a surfeit of aqua vitae" at Christmas.

[9] This act also made it technically illegal for anyone other than "the peers, gentlemen and freemen of larger towns" to distil spirits without a licence from the Lord Deputy.

[7] Another consequence was that the potential revenue lost to the exchequer through the under-reporting of output at legal distilleries and the tax avoidance of illicit producers became more significant, prompting Parliament to introduce the Distillers Act 1779 (19 Geo.

[7][16] This had the effect of concentrating licit distillation in a smaller number of distilleries based mainly in the larger urban centres, such as Cork and Dublin, which offered better markets for legal producers.

[16] The scale of this illicit activity was such that one surveyor estimated that duty was paid on only 2% of the spirit consumed in the northwestern provinces of Ulster and Connaught,[20] while Aeneas Coffey (an excise officer at the time, and later inventor of the Coffey still) estimated that there were over 800 illicit stills in operation in Inishowen, County Donegal alone.

[16][20] In addition, it prompted capital investments in establishing larger distilleries (which were more easily regulated), due to the need for economies of scale to profit from legal distillation.

[16] In fact, so much illicit spirit was available during this period that the licensed distillers in Dublin complained that it could be obtained "as openly in the streets as they sell a loaf of bread".

[21] In 1823, the authorities, acknowledging the problems with the licensing system, cut the duties by half,[16] and introduced the Excise Act 1823 (4 Geo.

[16] In addition, restrictions on the type and capacity of stills used were removed, granting distillers more freedom to tailor their equipment.

Previously, duty was charged monthly, based on still output, meaning that distilleries paid tax on whiskey before it was sold.

[16] However, under the reforms, duty was to be paid only when the whiskey was actually sold, making its storage in bond more attractive, as less of the distillery's working capital would be tied up in already-taxed stock.

[16] Together, these reforms greatly improved the distilling landscape, leading to a drop in illicit whiskey production and a boom in investment in legal distilleries.

By 1825, however, the Old Midleton Distillery operated a 31,618-gallon pot still, which remains the largest ever built;[19] Note: the largest pot still in operation in the world (as of 2014), located next door in the New Midleton Distillery, are roughly half this size, at 16,498 gallons (75,000 litres).

[24] In fact, even by the late 1880s, only two of Ireland's then 28 existing distilleries were producing single malt whiskey, the rest steadfast in their devotion to "pure pot still".

By the late 20th century, the once-popular pure pot still whiskey had almost disappeared entirely, with only two specialist bottlings, Green Spot and Redbreast remaining in existence.

This made them cheaper to operate, as they required less fuel, and more efficient to run, producing a continuous, rapid output of spirit.

As a consequence of increasing the alcohol concentration in the product, Coffey stills removed some of the other volatile components responsible for flavour.

[18] For instance, John Jameson trialled a Coffey still at his distillery, but chose to not adopt the technology because he was not satisfied with the quality of product it produced.

[18] Therefore, in the face of opposition in Ireland, Coffey offered his still to the English gin and Scottish whisky distillers, who proved more receptive, and where the technology gained widespread use.

After the laws were repealed in 1846, cheap American corn could be imported and used to produce neutral spirit in Coffey stills.

Despite changing tastes and falling market share, the adoption of Coffey stills was stubbornly resisted by Irish distillers for many years, with some arguing for restrictions on their use.

For instance, in 1878, the big Dublin distillers jointly published a pamphlet entitled Truths about Whisky, in which they referred to the output of Coffey stills as "Good, bad or indifferent; but it cannot be whiskey, and it ought not to be sold under that name".

[26] In 1909, the royal commission settled the argument, declaring that whiskey could refer to the output of either Coffey or pot stills.

Together, these factors greatly hampered exports and forced many distilleries into economic difficulties and out of business, and by the early 20th century Scotland had surpassed Ireland to become the world's largest whiskey producer.

Since the 1990s, Irish whiskey has undergone a major resurgence, and for the next twenty years it was the fastest growing spirit in the world, with annual growth of approximately 15–20% per annum.

Irish distillers, who operated under rules less strict than those applying to Scottish producers, experimented with new flavours, methods and cocktails.

[29] Irish whiskey has a smoother finish as opposed to the smoky, earthy overtones common to Scotch whisky, which come largely from drying the malted barley using peat smoke.

[40] However, many of these were recently established and had not yet aged their own spirits for sale as whiskey: Further distilleries are either planned or in development across Ireland.

[19] Irish whiskey comes in several forms, with the name of the style depending on the type of grain used and the distillation process.