At what stage shall I add whisky for Irish coffee? When preparing Irish coffee in a saucepan (caramelizing sugar&amp;coffee, then adding water);  

Should I add the whisky while coffee is still being heated in the saucepan or after putting the coffee in glasses?
At the end, after pouring the coffee into glasses. Alcohol evaporates entirely at 78'C but begins to evaporate before that, so any unnecessary heating should be avoiding. The coffee is cooled slightly by being poured into a glass, so that's the optimum time.

Source: being Irish.