Whiskey is a type of distilled alcoholic beverage made from fermented grain mash. Drinking it increases Strength and Charisma by one point while lowering Intelligence by the same amount. Whiskey is an addictive beverage. The brand most typically found in the wastes is the Olde Royale premium whiskey.
Whiskey has a slight orange glow to it, although not nearly as bright as Nuka-Cola Quantum. As well as other hard liquor, whiskey provides a minor status boost - increasing Charisma and Strength by one, while reducing Intelligence by one.
This section is needed but has not been written yet. You can help The Vault by writing it.
If you look closely at the label on the bottle, you can see a picture of Galileo Galilei in the lower right hand corner.
Behind the scenes
One can safely presume that this is an American whiskey, despite the reference to a monarch, as the English spelling of whiskey lacks an 'e'. Furthermore, Scotch is a protected item and may only come from Scotland, thus eliminating the need for a British whiskey.
SatCom Array NN-03d has miniature versions of full and empty whiskey bottles being used as chess pieces in an upstairs room. This is a possible reference to the movie (and novel) Our Man In Havana, in which a game of chess is played with miniature bottles of whiskey instead of regular chess pieces.