A few years back I came across this drink on the menu at Sidebar, a nice little neighborhood restaurant in Oakland. The menu attributed the drink to The Gentleman's Companion Vol. II by Charles Baker. At the time, I had never heard of Mr. Baker or his book, so I went out and grabbed a copy for myself. The book - republished as Jigger, Beaker & Glass - Drinking Around the World immediately became a staple of my cocktail library.
Here was the recipe according to Charles Baker:
Castle Harbor Special (original)
Jigger, Beaker & Glass - Drinking Around the World - By Charles Baker
1 1/2 jigger (2 1/4 oz) Barbados, Demerara or Martinique rum*
1/2 jigger (3/4 oz) White Bacardi rum
1 tsp. sweet pineapple soda fountain syrup
1 tsp. grenadine (optional)
juice of 1/2 lime
4 small dices of ripe pineapple
* The book references the Gosling Brothers. Gosling's is a Barbados rum - so I went with it
Combine all ingredients in a bar (mixing) glass and stir with a lump of ice. Turn contents into a small goblet half filled with cracked ice.
So first off, the ratios of spirit to sweetener were a little off. Perhaps the book was referring to a different jigger measurement - as you can see here the term jigger is not necessarily a fixed measurement depending on when and where it is based. So I toned down the alcohol contents slightly to 1 1/2 oz Gosling's Black Seal (I used 80-proof) and 1/2 oz white Bacardi. I opted to keep the grenadine (just a dash) and used 1/2 oz of Small Hand Foods pineapple gum syrup in the place of the fountain syrup and the pineapple slices.
I was pretty skeptical about mixing Gosling's in anything but a Dark & Stormy - but surprisingly the drink did work reasonably well. I also tried the drink with a La Favorite rhum vieux from Martinique (not good) and with a El Dorado 5-year Demerara rum (which worked well).
Finally I got the bright idea to ask the barkeep at Sidebar, and they were using a Jamaican rum for their adaptation of the drink. This was the clear winner to me. I found that the best option was an Appleton V/X, but the Coruba Dark in my cabinet also worked as a "well" option.
Castle Harbor Special (Adapted)
Adapted from Jigger, Beaker & Glass - Drinking Around the World - By Charles Baker
1 1/2 oz Appleton Estate V/X rum
1/2 oz pineapple gum syrup
juice from 1/2 a lime (should be 1/2 oz)
dash of grenadine
Combine all ingredients in a your shaker with several cubes of ice. Shake well, then pour entire contents (including the ice) into a double old-fashioned glass. Drop the spent half a lime in the glass and serve.
I like this adaptation of the drink because I really love Appleton V/X in general and in this cocktail the spirit picks up an herbaceous undercurrent. This is no brawny cocktail - the lime keeps this drink fresh and light, and the pineapple gum and grenadine add a little taste of the beach to the drink.
And no worries - if you bought a Bacardi 8 for your 10-Bottle Bar it also will work for this drink. If you really like the drink then try the Appleton V/X next time.
The Castle Harbor was one of my earliest money drinks (meaning that it is one of those drinks that you use when you have an uncertain or skeptical patron). Its also a great cocktail for anyone to try out from the 10-Bottle Bar.