Following Britain's conquest of Jamaica in 1655, a half pint or "2 gills" of rum gradually replaced beer and brandy as the drink of choice. Given to the sailor straight, this caused additional problems, as some sailors would save up the rum rations for several days, then drink them all at once. Due to the subsequent illness and disciplinary problems, the rum was mixed with water. This both diluted its effects, and delayed its spoilage. A half pint of rum mixed with one quart of water and issued in two servings before noon and after the end of the working day became part of the official regulations of the Royal Navy in 1756 and lasted for more than two centuries.
Admiral Edward Vernon had citrus juice (usually lime or lemon juice) added to the recipe to cut down on the water's foulness. Although they did not know the reason at the time, the Admiral’s sailors were actually healthier than the rest of the navy due to the daily doses of vitamin C that prevented disease (mainly scurvy). Eventually this custom got the British the nickname ''limeys'' (because of the limes they consumed).
History buffs like me will be interested to know that a subordinate and good friend of Admiral Vernon was a man named Lawrence Washington. Lawrence thought so much of the Admiral that he named his Virginia plantation after him. When Lawrence died the ownership of his plantation, Mount Vernon, passed to one George Washington.
George Washington, by the way, was a big fan of rum. His favorite drink was called “Fish House Punch”. Here is the recipe:
1 qt Cognac
3/4 lb. sugar
2 qts. water
1qt. lemon juice
peach brandy, 1 wine glass
Put sugar and water in a punch bowl and stir to dissolve .
Add rest of liquids.
Put large chunk of ice in punch bowl.
As a dedicated student of history myself, I once found it necessary to serve this drink at a small gathering in my home one evening, just for historical accuracy you understand. I learned 2 important things from the experience. First, it goes down far too easily after the first drink, and second, hide the car keys before serving this punch.
One last little note for my favorite Admin Officer: In the civilian world, a drink that is somewhat similar to grog is the fashionable Mojito. Starting with the basic recipe for "navy grog" and adding mint plus substituting carbonated water in lieu of plain water creates a basic Mojito.
OK, now I’ve made myself thirsty. I think it’s time for me to “splice the main brace”.