I know that, in general, Scottish whiskey is peaty because of the way they dry the malt with peat smoke while Irish whisky is not because they use unpeated malt. Is the difference legally established in these two countries or is it convention? Can an Irish distillery make Scottish whiskey and vice versa?
An Irish Whiskey is distilled in Ireland and aged for a minimum of three years in oak barrels.
Thus an Irish distillery can not produce a Scottish whisky!
However our question does not end here because the Scotch Whisky Regulations 2009 define five categories of Scotch Whisky:
•Single Malt Scotch Whisky: A Scotch Whisky distilled at a single distillery using only malted barley.
•Single Grain Scotch Whisky: A Scotch Whisky distilled at a single distillery.
•Blended Scotch Whisky: A blend of one or more Single Malt Scotch Whiskies with one or more Single Grain Scotch Whiskies.
•Blended Malt Scotch Whisky: A blend of Single Malt Scotch Whiskies which have been distilled at more than one distillery.
•Blended Grain Scotch Whisky: A blend of Single Grain Scotch Whiskies which have been distilled at more than one distillery.
But some Scotch Whiskies have a smoky flavor which originates from the peat fire over which the green malt is dried, prior to grinding and mashing.
Hold on for one moment, "in Ireland, whiskeys distilled at Cooley are only distilled twice, and they make smoky whiskeys there too (Connemara)."
Thus the question as what the differences are between an Irish Whiskey and a Scotch whisky, other than how one spells whiskey remains a question of geography!