A theory of relativity should drive any investigation into what is perhaps the most classic of cocktails: the Manhattan. The brown spirits version and forerunner of the clear Martini, this mix of whisky and vermouth is simple, yet remarkably variable. Making it right hangs on perfecting the ratio of ingredients, and any dedicated Manhattanite will rejigger it to suit each brand he pours. To prove the point we embarked on a volatile Manhattan Project, testing a list of superior Bourbons in proportions of two-, three- and four-to-one with vermouth. The results, while not explosive, were sublime.
We tested under laboratory conditions, with control elements that included the formidable Martini & Rossi Rosso (sweet) vermouth, two dashes of The Bitter Truth orange bitters, and plenty of ice. We shook each drink for 20 seconds. Impressions are arranged alphabetically.
Bulliet Bourbon Frontier Whiskey (90 proof), with its rye-heavy recipe, was best-served at a 2-to-1 ratio, where its character of Christmas spices popped.
Buffalo Trace combines sweet vanilla and spices, both of which shined at 2-to-1, allowing the bitters to come through.
The Evan Williams Single Barrel Vintage 2000 (86.6 proof) spoke of vanilla and caramel and found its stride at the intermediate ratio, revealing wood and nuts.
Another high-rye profile Bourbon, Four Roses Small Batch (90 proof), smacks of licorice and cloves, and it showed off well when mixed 3-to-1, with hints of spiced apple appearing.
We chose the new Maker’s Mark 46 (90 proof), which adds wood and nuts to the smooth and vanilla-informed original version, and found that a 3-to-1 ratio accommodated the flavor better than the stronger mix we prefer with the standard Maker’s.
We hesitated to try the new Knob Creek Single Barrel Reserve at 4-to-1 because of its 120-proof strength. Our instincts were right. Much better to back off to 2-to-1 where the whiskey’s sublime mix of caramel and spice also exhibits chewy orange and citrus character.
Smoothness and drinkability mark the Tennessee sour mash Jack Daniel’s Single Barrel (94 proof) and predictably, it didn’t need much vermouth (4-to-1) to best frame its elegant charms.
Likewise, the superbly balanced and elegant Jefferson Reserve Very Old (90.2 proof) was overwhelmed at 2-to-1 and showed its sophistication (and licorice) at a 4-to-1 ratio.
Despite the high proof of Wild Turkey Rare Breed (108.2), we found it balanced best at a 4-to-1, mainly since it’s so sweet and complex—with orange peel, spice, maple and flowers—that adding too much vermouth was overkill.
Woodford Reserve Distiller’s Select (90 proof) is a classic sweet Bourbon, meeting vanilla tones with fruits like cherries, and doesn’t need much vermouth to make the point. It was at its most sultry and inviting at 4-to-1.
And variables don’t end there. There’s garnish (cherry or a lemon twist), classic sweet or dry vermouth (or mix them) and the bitters choice. You could even make it with rye whiskey, but that’s another article.