Let’s say I am adding 70Kcals worth of white wine to my dish but as I cook it down the alcohol evaporates. Does this mean that the energy content of the evaporated alcohol also “leaves”?
Yes, the ethanol in the drink will evaporate and thus you get less and less of the drink as it is being cooked and after it sits out. Wine generally evaporates at .5% per hour just by sitting out in the open, and it starts to evaporate faster at 172 Fahrenheit. You can complete cook out the alcohol in wine in about three hours.