How to Make a Perfect Penicillin Cocktail at Home
The penicillin cocktail is a modern classic that combines blended Scotch, fresh lemon juice, honey-ginger syrup, and a smoky Islay Scotch float to create a balanced, warming drink perfect for whisky lovers. Created by Sam Ross at New York's Milk & Honey bar in 2005, this cocktail has earned its place on the International Bartenders Association official list and continues to grow in popularity among home bartenders.
We tested dozens of variations and shaker types to find the best way to make this drink at home. Whether you're new to cocktails or already mixing moscow mule variations and other craft drinks, this guide will walk you through the ingredients, tools, and technique you need.
Essential Penicillin Cocktail Ingredients
The ingredient list is short but each component plays a specific role in the final flavor profile.
- Blended Scotch whisky (2 oz): Forms the base of the drink. Choose a smooth, approachable blend like Famous Grouse or Monkey Shoulder rather than a heavily peated single malt.
- Fresh lemon juice (¾ oz): Provides bright acidity. Always squeeze fresh; bottled juice lacks the vibrant flavor this cocktail needs.
- Honey-ginger syrup (¾ oz): Adds sweetness and spice. You'll make this by simmering equal parts honey and water with fresh sliced ginger for 10 minutes, then straining and cooling.
- Islay Scotch float (¼ oz): The signature smoky cap. Laphroaig or Ardbeg work beautifully, poured gently over the back of a bar spoon so it floats on top.
- Candied ginger (optional): A classic garnish that reinforces the spice notes.
The honey-ginger syrup is what sets this recipe apart from simpler whisky sours. Serious Eats recommends making a batch ahead of time since it keeps refrigerated for up to two weeks and lets you mix the cocktail quickly when the mood strikes.
Best Shaker for Making a Penicillin Cocktail
A proper shaker is essential because this drink requires vigorous shaking to chill, dilute, and emulsify the honey syrup with the other ingredients. We tested this recipe with several shaker styles and found the boston shaker offers the best combination of capacity, ease of use, and temperature control.
Here's how the common shaker types compare for making whisky cocktails:
| Shaker Type | Best For | Drawback |
|---|---|---|
| Boston shaker | Single or double servings, excellent dilution control | Requires separate strainer |
| Mini cocktail shaker | Single serving, compact storage | Limited capacity for ice |
| Cobbler shaker | Beginners, built-in strainer | Cap can freeze shut, harder to clean |
For a full-sized penicillin cocktail recipe with plenty of ice, a standard alcohol shaker gives you room to shake hard for 12 to 15 seconds without worrying about overflow. The vigorous shaking is crucial because honey syrup is thick and needs that action to fully integrate.
If you're making a single serving for yourself and want something more compact, a mini martini shaker works well, though you'll need to use slightly less ice to leave room for shaking.
Step-by-Step Penicillin Cocktail Recipe
Follow this method for a balanced, properly diluted drink every time.
- Make the honey-ginger syrup (if you haven't already): Combine 1 cup honey, 1 cup water, and a 3-inch piece of fresh ginger (sliced) in a small saucepan. Simmer for 10 minutes, strain out the ginger, and let cool completely. Store in the refrigerator.
- Add ingredients to your shaker: Pour 2 oz blended Scotch, ¾ oz fresh lemon juice, and ¾ oz honey-ginger syrup into the larger tin of your shaker.
- Add ice and shake: Fill the shaker two-thirds full with ice cubes. Seal and shake hard for 12 to 15 seconds until the outside of the tin is frosty cold.
- Strain into a rocks glass: Fill a rocks glass (also called an old fashioned glass) with fresh ice. Strain the cocktail over the ice using a Hawthorne strainer.
- Float the Islay Scotch: Pour ¼ oz of your chosen peaty Scotch over the back of a bar spoon held just above the drink's surface. This creates a smoky layer on top.
- Garnish: Add a piece of candied ginger on a cocktail pick or simply drop it into the glass.
The penicillin cocktail recipe delivers a complex drinking experience. The first sip brings forward the smoke, then the honey-ginger sweetness and whisky warmth, finishing with bright lemon acidity. The Kitchn's version notes that the drink tastes like a whisky sour that went to finishing school.
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Penicillin Cocktail Variations to Try
Once you've mastered the classic recipe, these variations add new dimensions while keeping the drink's character intact.
Adjust the peat: If you find the Islay float too smoky, reduce it to ⅛ oz or try a lighter peated whisky like Bowmore or Highland Park. Conversely, peat lovers can increase the float to ½ oz for a bolder finish.
Swap the base spirit: A bourbon penicillin uses the same proportions but substitutes bourbon for Scotch and skips the smoky float (since bourbon doesn't traditionally pair with peat). The result is sweeter and rounder.
Add heat: Muddle a thin slice of fresh jalapeño in the shaker before adding the other ingredients for a spicy kick that plays beautifully with the ginger.
Make it a double: For a party, scale the recipe to 4 oz Scotch, 1.5 oz lemon, and 1.5 oz syrup in a large shaker, then strain into two glasses and float ⅛ oz Islay on each.
If you enjoy experimenting with different recipes, our guides to ireland coffee and other classic cocktails offer more ways to use your boston shaker setup.
Tips for the Best Home Penicillin Cocktail
These details make the difference between a good drink and a great one.
- Use fresh lemon juice only: Bottled juice oxidizes and tastes flat. The bright, tart flavor of fresh-squeezed lemon is non-negotiable in a cocktail with this few ingredients.
- Don't skip the hard shake: Honey syrup needs aggressive shaking to emulsify properly. A lazy 5-second shake leaves the drink unbalanced and syrupy.
- Chill your glass: If you have time, put your rocks glass in the freezer for 10 minutes before building the drink. A cold glass keeps everything at the perfect temperature longer.
- Quality Scotch matters: You don't need to buy expensive bottles, but avoid bottom-shelf blends. The whisky is the star here, so choose something you'd drink neat.
- Fresh ginger is essential: Ground ginger powder won't give you the bright, spicy flavor the syrup needs. Buy a knob of fresh ginger and slice it thin for maximum surface area.
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Who Should Try This Cocktail
The penicillin cocktail suits anyone who enjoys whisky-forward drinks with complexity. If you already love whisky sours, old fashioneds, or even smoky mezcal cocktails, this drink will feel familiar yet exciting.
It's also an excellent choice for cold weather sipping. The honey-ginger combination has a warming quality that makes this cocktail feel like a sophisticated remedy for a chilly evening, which is exactly what Sam Ross had in mind when he named it after the antibiotic.
Because the recipe requires fresh syrup prep, it's best for home bartenders who like to batch components ahead rather than those seeking a 30-second pour-and-serve option. Once you have the syrup made, though, each cocktail comes together in under two minutes.
Whether you're building your first home bar or already mixing Cocktail xdirtymartini and other complex recipes, the penicillin cocktail deserves a permanent spot in your repertoire.
Frequently asked questions
What does a penicillin cocktail taste like?
A penicillin cocktail tastes like a smoky, honey-sweetened whisky sour with warming ginger spice. The Islay Scotch float adds a distinctive peat smoke aroma that hits your nose before the first sip, while the honey-ginger syrup balances the tart lemon juice.
Can I make penicillin cocktail syrup ahead of time?
Yes, honey-ginger syrup keeps in the refrigerator for up to two weeks in an airtight container. Making a batch ahead means you can mix the cocktail in under two minutes whenever you want one.
What Scotch should I use for a penicillin cocktail?
Use a smooth blended Scotch like Famous Grouse, Monkey Shoulder, or Johnnie Walker Black for the base, and a heavily peated Islay Scotch like Laphroaig or Ardbeg for the float. Avoid using expensive single malts since the other ingredients will mask their nuance.
Do I need a boston shaker to make this drink?
No, but a boston shaker or standard alcohol shaker works best because you need room for ice and vigorous shaking to properly emulsify the honey syrup. A mini shaker can work for a single serving if you reduce the ice slightly.
Can I make a penicillin cocktail without the smoky float?
Yes, though the Islay Scotch float is the drink's signature element. Without it, you have a very good honey-ginger whisky sour, but you lose the complex smoky aroma and layered flavor that makes the penicillin unique.
How strong is a penicillin cocktail?
A standard penicillin cocktail contains 2.25 oz of whisky total, making it a spirit-forward drink similar in strength to an old fashioned or manhattan. The honey, ginger, and lemon balance the alcohol but don't hide it.