Diamonds are created by unimaginably powerful natural forces. A Black Diamond, then, must require nothing short of enchantment. How else could you turn whiskey and blackberries into a cocktail that not only impersonates a luscious Bordeaux but also expands on its flavors? Much of the secret is in the fruit, the way its plump sweetness rolls into the angular precision of the whiskey in a yin-yang, push-pull magic trick.
Fruit is the most ephemeral of jewels, ripening and fading in strict season. Humans have long sought to preserve it past its time, but we have also learned to appreciate the inevitable fermentation. Thus the global panoply of wines and spirits. (It is not just people who have become connoisseurs of decay; bears and elephants are said to wait for fallen fruit to reach the right level of over-ripeness to enjoy its intoxicating effect.)
Part of the modern mixologist’s art is to play with these variations of time, combining the liquid of ferment with the vital juice just squeezed from the freshest fruit. Accordingly, you need to get things just right to make a proper Black Diamond. John deBary of the Manhattan bar PDT doesn’t serve the drink he invented all the time—only when blackberries are at their peak. Thus, to experience this exquisite potion as its creator intended, you have just a three-to-four-week window in the summer. Timing is everything.
The Black Diamond may take meticulousness to an extreme, but there are simpler ways to enjoy seasonal fruit in your cocktail. Citrus, for example, has a relatively long season in the colder months. Bernard Sun, beverage director for the restaurant empire of chef Jean-Georges Vongerichten, serves a gorgeous blood-orange mimosa in the winter and early spring. When April and May set in, the Jean-Georges kitchens cook down rhubarb to combine with elderflower syrup and champagne for a seductive Bellini. And come summer, Arley Marks, bartender at the New York City branch of Mission Chinese Food, turns to ripe cantaloupe, which he combines with the Korean liquor soju to create the T-1000. Named for one of the more pernicious characters in the movie Terminator 2, the cocktail is a perfect match for the capsaicin-stoked fire of the restaurant’s spiciest dishes. Rather than stanch the characteristic heat of Sichuan food, it leaves a layer of flavor that makes you want more.
The wonder of refrigeration, of course, can solve many problems of seasonality. Momofuku Ssäm Bar has the Menthe Concorde, for instance. Concocted by deBary, who also works as the bar manager for the Momofuku Group, the drink features Concord grapes that have been frozen at their late-summer peak for year-round use.
And while the flesh of the berry usually receives top billing, don’t forget its seed. The Randolph on Broome, a coffee bar by day and a mock speakeasy by night in New York City’s Chinatown, has the Double Punch: mainly iced coffee—no milk—and pisco (a Latin American grape brandy). It is a lovely and buzzy reminder that coffee beans emerge from the coffee berry—a fruit that provides for all seasons.