Distilled Knowledge Cocktail: The Greyhound
(Not sure what the title means? The Distilled Knowledge announcement should fill in the gaps.)
I'm counting down the days to publication with a series on the cocktails mentioned in Distilled Knowledge. They're an odd bunch, I'll grant, but each serves a purpose in the narrative.
Pride of place goes to the Greyhound, the cocktail that taught us not to mix grapefruit juice with medicine.
As you may have heard, it's a bad idea to drink grapefruit juice if you're on any kind of prescription drugs. It has a tendency to lead to higher-than-intended blood concentrations of your medications, with consequences that range from "mildly inconvenient" to "literally fatal."
You may not know that we learned this entirely by accident.
Researchers were studying the effects of ethanol on a blood pressure medication called felodipine. It was important for the experiment's success that the subjects not know whether they'd been given booze or not, so the researchers tried a variety of mixers (for science!) and concluded that the taste of the alcohol was best masked by grapefruit juice.
In the course of the study, they found that their subjects' blood felodipine levels were higher than expected across the board. Imagine their surprise when they realized they'd made a major scientific discovery "following an assessment of every juice in a home refrigerator one Saturday evening."
Distilled Knowledge Greyhound
2 1/2 oz. Double-Strength White Grapefruit Juice
1/2 oz. Vodka
Stir with ice. Serve on the rocks.
If what you're looking for is a drink with the taste of the booze completely hidden, mixing five parts grapefruit juice with one part vodka is a surefire way to get there. It is not, however, the way the cocktail is ordinarily served; merely an approximation of the concoction the felodipine researchers were using.
Note that if you'd like to add felodipine to this drink and make a Felodipine Greyhound, do not do so under any circumstances. Did you know that it's possible for your blood pressure to be too low? It is, and you don't want to find out what that's like.
On the other hand, there are many other versions of the Greyhound that don't threaten your health nearly as much. These days, it's commonly made with a 3:2 or a 2:1 ration of grapefruit juice to vodka. Personally, I prefer the former; grapefruit juice can be quite a lot when it's the majority of a drink by volume.
Contemporary Greyhound
3 oz. Fresh Grapefruit Juice
2 oz. Vodka
Prepare as above.
I still advise stirring, because shaking a drink that's mostly juice by volume just seems excessive. Note that a fresh grapefruit will yield about 3 oz. of juice, and the Greyhound needn't be a particularly exact drink; if you'd like to remember the recipe as "two ounces of vodka and a grapefruit," I won't stop you.
With a pinch of salt and more around the rim, this becomes the Salty Dog, which I assume is so called because "salty Greyhound" doesn't have the same ring.
With a gin base instead of a vodka one, it becomes...the Greyhound. Yes, this is one of the (many) cocktails that got its start as a gin drink and evolved into a vodka one as tastes changed.
It's first attested in the Savoy Cocktail Book, where it's mentioned as a variation on the older Grapefruit Cocktail, a concoction involving grapefruit jelly. In any case, it was a gin drink, and it would be some years before vodka came into vogue this far west.
Savoy Greyhound
"Take three and a half glasses of Gin and the juice of 1 1/2 good-sized Grapefruit. Sugar to taste, plenty of ice. Shake and serve."
Near as I can figure, that works out to about seven ounces of gin, four and a half ounces of grapefruit juice, and sugar to taste. This would have been a batch, with each drink closer to three ounces total. Still boozier than the modern version, and much ginnier-tasting.
Once introduced to vodka, the Greyhound ran off with it and never looked back. And honestly, I can't blame it; I say this very rarely, but I think this drink makes more sense with vodka. It's a simple cocktail. It hits a few notes (sour, bitter, ethanol) and it hits them hard. Tossing juniper in there seems more distracting than enhancing in this case, and I expect most people who Really Like Gin will prefer not to cover its flavor with an even larger dose of grapefruit.
That'll do it for the first installment. Stay tuned for more!