I used to hear people talk about “slow” gin, and I thought it was gin produced by a process that took longer than “quick” gin of the bathtub variety. Or perhaps it was the beverage Robert Benchley had in mind when a friend warned him that Martinis were slow poison, and Benchley replied, “That’s all right, I’m not in any hurry.” Now in my dotage, I have come to understand that it isn’t “slow” gin at all, but “sloe” gin.
The sloe is a kind of plum, defined in rapturously poetic terms by the Merriam-Webster Collegiate Dictionary as the “small dark globose astringent fruit of the blackthorn.” A liqueur called sloe gin is made by soaking the blackthorn fruits for a long, long time in regular London dry gin.
The word sloe descended from the Middle English slo and Old English slāh, meaning plum. It is related to Russian sliva, and it shows up in slivovitz, the plum brandy made in many Slavic countries. The root word is also cognate with the words lavender and livid, which originally meant purplish (like a plum) from bruising, and now can mean blue-black, gray, reddish, or simply angry.
Plagiarizing the poetry of Merriam-Webster's definition, the Bard of Buffalo Bayou, whose lips have never touched sloe gin, offers this paean to the fruit:
O, small and dark and globose fruit,
Astringent fruit, how succulent!
I scratched my hand on your blackthorn,
And now I’m feeling truculent.