A lesser known cocktail from Tiki's Golden Age.
While I often write about Don the Beachcomber and Trader Vic, there was a third pillar of the Tiki movement by the name of Steven Crane. While he was a bit later to the party, Crane elevated Tiki bars to palaces with the Luau in Beverly Hills and his Kon-Tiki chain collocated with Sheraton's top properties. The level of success Crane had with his Kon-Tiki restaurants is truly amazing. The high volume required a level of skill (by the bartenders) and management strategies unlike anything I've seen in my lifetime.
How about a few numbers to see what I mean? In 1958 Sheraton put up $4 million for 9 Kon-Tiki restaurants to be built. That's more than $36 million in 2020 dollars. The first opened at the Montreal Sheraton in 1959 where it made $750,000. (that's $6.7 million in 2020 dollars) The average Kon-Tiki had 15 bartenders split between two service bars and a front of house bar. Between them all they would go through 240 bottles of booze per night at their peak while being expected to master the 115 tropical cocktails available. This ended up going to 22 bartenders so that you could rotate guys out every hour to account for breaks. The entire operation was run like an assembly line with one bartender pouring, another mixing (up to 15 mixers per station), another garnishing, and so on. Beachbum Berry's Sippin' Safari goes into great detail about not only Kon-Tiki's operating procedures but the life stories of some of their most notable bartenders. If you find this interesting in the least I'd highly recommend reading the full story.
Which brings us to the Rain Killer. This drink was served at the Kon-Tiki chain and as such it adheres to Steven Crane's 50/50 rule. Crane thought a good tropical cocktail should be 50% liquor and 50% mixers. Crane and his bar managers (like Bob Esmino and Ray Barrientos) also eyed the Kon-Tiki recipes with an eye toward the speed necessary to keep up at a Kon-Tiki bar. They really worked to streamline the portions for fast assembly. The Rain Killer is pretty close to 50/50 and there aren't any of Don the Beachcomber's 1/8 ounce of this or 6 drops of that here. That balance also means that it is very malleable. For example, while the original calls for light Puerto Rican rum, at Kon-Tiki they would routinely sub whatever liquor the guest preferred as the drink works quite well with vodka, gin, and bourbon. I stick with rum but even there you can change this drink quite a bit. I'm betting Cruzan white is closest to the original as served in at Kon-Tiki but my current preference is Plantation 3 star due to it's added body with it being a blend of 3 different rum styles. I also like this with Brugal white. It (like most Brugal offerings) is quite dry for a rum which makes the Rain Killer seem a bit more crisp.
Source - Sippin' Safari, Jeff "Beachbum" Berry
1/2 ounce lime juice
1/2 ounce orange juice
1/2 ounce pineapple juice
1/2 ounce simple syrup
1 1/2 ounces white Puerto Rican rum*
dash Angostura bitters
Build everything in a mixing tin and flash blend for 5 seconds with crushed ice using a spindle mixer. Serve in a stemmed cocktail glass. Garnish is a mint sprig and a paper umbrella.
*Bamboo Sam's customizations: While I understand using some bottled juices there is no excuse for not using fresh limes. And if yu really want this thing to sing, use fresh OJ and pineapple juice as well. As I said earlier, my preferred rums for the Rain Killer are 1) Plantation 3 Star, 2) Brugal White, 3) Cruzan White, or 4) whatever you have on hand.