Essential Whisky Cocktail: Penicillin

Before the early 2000s, the idea of using single malt scotch in a cocktail was virtually blasphemous. But in 2005, Sam Ross received a shipment of Compass Box whiskies at legendary New York City bar Milk & Honey. And, as any bartender would, he started playing around with them. Eventually he decided to try a variation on the Gold Rush (bourbon, lemon, and honey), adding ginger juice and topping it with Peat Monster. (To be fair, Peat Monster is a blended malt scotch, but any peated Islay single malt works just as well.)

At the time, Ross didn’t think much of his creation. But now that drink, the Penicillin, has become a modern classic served in bars globally.

“It’s a perfect example of someone who knows the mastery of making cocktails,” says Leo Robitschek, bar director of the NoMad Bar in New York City. “You think about what each ingredient adds to the cocktail, then what to adjust to balance it.”

At the time he created the Penicillin, Ross worked at New York City cocktail den Milk & Honey, which was run by the innovative and well-regarded bartender Sasha Petraske. “I think that’s what gave it the legs to become a standard cocktail every bartender wants to know how to make,” says Marshall Minaya, head bartender at Valerie in New York City, referring to Petraske’s influence.

The familiar ingredients that combine into a sweet, spicy, smoky cocktail also appeal to most people, especially in the winter. “Honey and ginger is a flavor we all know from when we were sick and took cough drops, or our mom made tea with lemon, ginger, and honey—so it’s comforting,” Robitschek says. The name Penicillin is, in fact, a nod to the medicinal properties of some of the drink’s ingredients.

But that doesn’t mean the Penicillin is only a cold-weather drink. In fact, some bars like Brooklyn’s Diamond Reef make a “Penichillin” variation in the summer, adding ice and blending it into a slushie.

Choose Your Whisky

The Penicillin’s base spirit is a neutral blended scotch, says Robitschek, who recommends Famous Grouse. Minaya prefers Pig’s Nose or Monkey Shoulder, which is a blended malt. “The flavor profiles of these two scotches are balanced and not overly smoky,” he explains.

For the float, it has to be a peaty Islay scotch, and both Minaya and Robitschek say Laphroaig is the way to go. “At Valerie we use Laphroaig 10 year old,” Minaya says. “It has all those nice peaty notes on the nose as you raise the glass to your lips, along with hints of seaweed and sea salt.”

A truly modern whisky cocktail, the Penicillin has become a classic thanks to its deft combination of peated scotch, ginger, lemon, and honey. (Photo by Ian J. Lauer)

Penicillin Recipe

  • 2 oz. blended scotch whisky
  • ¾ oz. lemon juice
  • ⅜ oz. ginger syrup (See below)*
  • ⅜ oz. honey syrup (3:1 ratio of honey:water)*
  • 1 splash peated Islay single malt or blended malt scotch
  • 1 piece candied ginger, to garnish

Add all ingredients except the peated scotch to a shaker with ice. Shake well for 8 to 10 seconds. Strain over a large ice cube or several smaller cubes in a rocks glass. Float peated whisky on top by slowly pouring it over the back of a spoon, and garnish with candied ginger.

To make ginger syrup: Peel and juice raw ginger root to extract 1½ cups juice. Transfer to a medium saucepan over medium heat and add 1½ cups granulated sugar. Stir constantly until sugar is dissolved, about 5 minutes. Keep refrigerated in a nonreactive glass container, like a mason jar, for up to two weeks.

*The unusual ratio of honey and ginger syrups adds up to ¾ ounce of sweetener. It can be difficult to measure, so aim for just less than ½ ounce of each.

Top Tips

Chill your glass
The Penicillin is best enjoyed super cold, so put the rocks glass in the freezer for a few hours.

Use fresh citrus
If you pull out a mushy lemon that’s been in your fridge for two weeks, you will taste the difference—and it won’t be a good one. Buy fresh citrus anytime you make a cocktail.

Don’t replace the ginger syrup
“The drink will not taste the same with ginger liqueur or muddled ginger,” Robitschek says.

Shake hard
“Shake like you mean it,” Minaya says. “Honey in a cocktail shaken vigorously leaves a nice foam on top of the drink once it’s poured.” He recommends an 8-10 second shake.

Remember, the Islay is a float, not a pour
If you’re too generous with the peaty scotch, it’ll overpower the drink. Stick to about ¼ ounce gently poured over the back of a spoon, Minaya says, “just for that little peat aroma.”

Make It Your Own

  • Try an agave twist called the Medicina Latina, Minaya suggests: Replace the scotch with mezcal (he recommends Montelobos), the lemon juice with lime, and the Islay scotch with a smokier mezcal like Del Maguey Vida.
  • If you’re more of a bourbon person, Minaya offers this variation served at Valerie: 1 oz. bourbon, 1 oz. aged rum, ¼ oz. Strega Liqueur, ¾ oz. lemon juice, ½ oz. honey, and ½ oz. ginger syrup. Shake well and strain.
  • Make a rum penicillin, but use only ¼ oz. of each syrup to balance the sweetness.
  • Or split the drink’s base between 1 oz. blended scotch and 1 oz. rum, Robitschek suggests. Keep the other ratios the same.

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