Ireland holds the earliest documentary claim in the history of whiskey. The Annals of Clonmacnoise record a death in 1405 attributed to a surfeit of aqua vitae, and in 1608 a licence to distil was granted in County Antrim to Sir Thomas Phillips — the earliest such licence known anywhere.
The spelling itself is a historical artefact. Irish distillers adopted the additional letter in the nineteenth century, in part to distinguish their product from Scotch at a time when the two competed directly in export markets. The convention persists: whisky in Scotland, Japan and Canada; whiskey in Ireland and, generally, the United States.
The Victorian ascendancy
For most of the nineteenth century, Irish whiskey led the world. Dublin's great distilleries — Jameson at Bow Street, Powers at John's Lane, Roe at Thomas Street — operated at a scale that dwarfed their Scottish counterparts. John Jameson's Bow Street site covered several acres of the city; George Roe's operation was, by some measures, the largest distillery in the world.
Their product was Single Pot Still whiskey, made from a mash of both malted and unmalted barley. The style had originated as tax avoidance: British legislation levied duty on malted grain, and Irish distillers reduced their liability by substituting unmalted barley. The technical consequence of that fiscal manoeuvre became the defining characteristic of an entire national category.
A tax on malted barley produced, quite accidentally, a production style found nowhere else in the world.
Collapse
The reversal was rapid and near-total. Dublin distillers rejected the Coffey still, regarding column-distilled grain spirit as an inferior product, and thereby ceded the blended market to Scotland. Political separation from Britain closed Commonwealth markets. Prohibition removed the United States. The Anglo-Irish trade war of the 1930s compounded the damage.
By the 1960s only a handful of Irish distilleries remained working. In 1966 the survivors in the Republic merged as Irish Distillers, and in 1975 concentrated all production at a new complex at Midleton in County Cork. By the 1970s the entire island's output came from two sites.
Preservation and revival
That consolidation, though it represented an industry at its lowest point, preserved the technical knowledge of pot still production. Midleton was designed with sufficient flexibility to reproduce the distinct characters of the labels it inherited, and Single Pot Still whiskey survived largely through the continuation of Redbreast and a small number of related expressions.
From the 1990s onwards the number of working distilleries on the island increased steadily, and the pot still category — reduced at one point to a single commercially available label — has been the subject of sustained archival research into nineteenth-century mash bills and production records. The revival is, in an unusually literal sense, a documentary project.