Penicillin
A small pool of smoky whisky sits on top of a Penicillin, reaching the nose before the lemon, honey and ginger beneath it reach the palate.[2][6] Sam Ross created this Scotch whisky cocktail at Milk & Honey in New York in 2005, taking the bourbon, honey and lemon combination of the Gold Rush in a new direction.[1][6]
What makes a Penicillin distinctive
Two whiskies do two different jobs: blended Scotch forms the base, while a smaller measure of peated whisky sits on the surface. The float goes on after shaking, rather than into the shaker with everything else.[2][6]
Ross captured the effect: “that little pool of smoke and peat sat on top of the drink and hit your nostrils before you tasted the mild, balanced concoction underneath”.[2]
The link to the Gold Rush is easy to follow. Where that drink combines bourbon, honey syrup and lemon juice, Ross changed the whisky and split the sweetening between honey and ginger. Milk & Honey already made the sweetened ginger juice he used.[1][4]
Origin: from New York to London
Compass Box samples gave Ross the starting point. An Australian bartender who moved to New York in 2004, he developed the Penicillin about a year later. Saveur’s account names the two whiskies: Asyla, a blend of grain and malt whiskies, formed the base, with “just a touch” of Peat Monster on top.[1][3]
From samples to a London menu
The samples became the foundation of the drink Ross created at Milk & Honey, New York, in 2005, according to Saveur’s account. Trade accounts identify Asyla and Peat Monster as the development whiskies, and Compass Box’s own account also names Peat Monster as the original smoky float.
The recipe then crossed the Atlantic. Kevin Armstrong reports that Sasha Petraske passed it to Milk & Honey’s London bar by its autumn and winter menu of 2006, as recorded in Club Oenologique’s account.
Claim and verdict: Compass Box samples gave Ross his base and float. Documented.
Editorial note: Saveur supports the creator, place, year and sample story; Club Oenologique supports the London transmission; Compass Box supports the producer’s account of the original float. The supplied record does not establish Ross’s exact quantities in 2005, and the earliest known source is not established from the supplied sheet. The editor must verify that source and its date before publication. Last checked: November 2026. The editor must record the full date of verification before publication.
The name has a different source. Ross told Saveur that it came from chicken noodle soup’s nickname, “Jewish Penicillin”. It is a culinary joke, not a statement that the cocktail has medicinal value.[1]
Penicillin recipe: Difford’s published specification
Difford’s Guide presents this specification as Sam Ross’s original. It is an attributed recipe, not a site tested reconstruction of the exact measures used in 2005.[6]
Prepare the syrup: allow a 12-hour steep
Difford’s uses 100 g sliced root ginger, one cup honey and one cup water. Simmer for five minutes, steep in the fridge for 12 hours, then strain.[6]
Recipe card
Serves: one
Glass: old-fashioned glass
Ice: ice for shaking and fresh ice for the glass
Garnish: skewered crystallised ginger
| Ingredient | Measure |
|---|---|
| Blended Scotch whisky | 60 ml (2 US fl oz) |
| Freshly squeezed lemon juice | 22.5 ml (¾ US fl oz) |
| Honey and ginger syrup | 22.5 ml (¾ US fl oz) |
| Peated Islay single malt Scotch whisky | 7.5 ml (¼ US fl oz) |
Method
- Add the blended Scotch, lemon juice and honey and ginger syrup to a shaker with ice.
- Shake, then strain into the old-fashioned glass filled with fresh ice.
- Float the peated Islay single malt on top, keeping it separate from the shaken ingredients.
- Garnish with skewered crystallised ginger.[6]
Use measured servings, offer water and food, and allow breaks if serving this as part of a tasting. Spitting is normal at tastings, and nobody needs to finish a glass.
Keep the distinction between the substantial blended Scotch base and the small peated addition. Replacing the entire whisky measure with smoky single malt changes this published recipe’s structure, not just the bottle used to make it.[6]
Why published versions differ
Fresh ginger, rather than a combined honey and ginger syrup, distinguishes the International Bartenders Association’s version. It calls for 60 ml blended Scotch, 22.5 ml lemon juice, 22.5 ml honey syrup, two to three quarter-size ginger slices and a 7.5 ml Islay malt float.[7]
In that method, muddle the ginger first. Shake everything except the Islay malt, then fine strain into a chilled old-fashioned glass containing ice. Float the malt afterwards and garnish with candied ginger. Both this and Difford’s are sourced versions of the Penicillin, but their instructions for preparing the ginger component are not interchangeable.[7]
Honey syrup strength matters, too. Club Oenologique reports ratios of 2:1 at Satan’s Whiskers and 3:1 at NoMad and Attaboy. Matching a bar’s liquid measures without matching its syrup preparation will not necessarily reproduce its drink.[4]
Common mistakes
Assuming it is an old cocktail. The Penicillin dates to 2005, when Ross created it, not to the years before Prohibition.[1][6]
Confusing the original float with later recipe choices. Compass Box identifies Peat Monster as the original float; later recipes name other whiskies. Saveur describes Peat Monster as a mix of Islay and Speyside whiskies. The International Bartenders Association specifies Lagavulin 16, while The Washington Post suggests Peat Monster or Laphroaig 10. Those later specifications do not by themselves contradict the account of the original float.[1][2][7][8]
Shaking in the entire smoky measure. Difford’s published method reserves the peated whisky for the surface. Club Oenologique reports later bar variations that shake some peated whisky into the base. That is a deliberate variation, rather than the method given above.[4][6]
Where to go next
- Whisky Cocktails: The Complete Guide: explore the wider cocktail family and its preparation methods.
- Gold Rush: follow the bourbon, honey and lemon drink behind Ross’s adaptation.
- Whiskey Sour: explore the sour structure connecting these drinks.
Sources
[1] Saveur. The Making of a Modern Classic Cocktail. Undated web feature, checked November 2026. https://www.saveur.com/making-modern-classic-cocktail/
[2] The Washington Post, M. Carrie Allan. Penicillin Cocktail. Undated recipe and accompanying account, checked November 2026. https://www.washingtonpost.com/recipes/penicillin/
[3] Imbibe Magazine. Three Ways: The Penicillin. Undated web feature, checked November 2026. https://imbibemagazine.com/three-ways-penicillin/
[4] Club Oenologique. The Anatomy of a Penicillin. Undated web feature, checked November 2026. https://cluboenologique.com/story/anatomy-of-penicillin-cocktail/
[6] Difford’s Guide. Penicillin. Web recipe, including the specification presented as Sam Ross’s original; checked November 2026. https://www.diffordsguide.com/cocktails/recipe/2539/penicillin
[7] International Bartenders Association. Penicillin. Official cocktail specification, web edition checked November 2026. https://iba-world.com/iba-cocktail/penicillin/
[8] Compass Box Whisky. Home page. Producer’s account, web edition checked November 2026. https://www.compassboxwhisky.com/en-us
This article was prepared as desk research from the supplied verified fact sheet, distinguishing attributed recipes, trade reporting and the producer’s own account.
Last checked: November 2026