Since Germany never gained independence from the UK by force of arms, it should be "whisky". This is a joke: given that they only have to fit the two data poin

Since Germany never gained independence from the UK by force of arms, it should be "whisky". This is a joke: given that they only have to fit the two data points of the USA and Ireland, one can make up any number of "rules" for whether it's "whisky" or "whiskey".