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With a quick and easy fennel simple syrup, some fresh squeezed grapefruit juice, vodka and club soda- this 4 ingredient Fennel Grapefruit Vodka Cocktail is dangerously easy to drink, and almost too easy to whip up!

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Fennel Grapefruit Vodka Cocktail with Fennel Simple Syrup

While not a well know flavor coupling, there is something that just clicks for grapefruit and fennel. The sweet, almost licorice flavor of the fennel syrup compliments the grapefruit juice and bite of the vodka perfectly.

Top that combo off with a little bubbly mineral water or club soda, and you’ve got a crisp, refreshing and oh-so-drinkable cocktail that’s ready in minutes, with a few simple ingredients!


To make the Fennel Grapefruit Vodka Cocktail, you will need:

  • 1.5 oz vodka.
  • 1/4 cup fresh squeezed ruby red grapefruit juice.
  • 1.5 oz fennel simple syrup (see below for recipe).
  • Chilled club soda, or sparkling mineral water.
Fennel Grapefruit Vodka Cocktail

Making the Fennel Simple Syrup

To make the fennel simple syrup for the Grapefruit vodka cocktail, you will need:

  • 1/2 tbsp fennel seeds. You can find these in the spice section of the grocery store.
  • 1 cup water.
  • 1 cup organic cane sugar or granulated sugar.

Cooking and storing the syrup

Throw everyone in the pool (aka the saucepan) and let them meld together into a richly colored, deeply flavored syrup. Once it’s cooled and strained, it’s ready to use- and store in the fridge for up to 2 weeks.

A 4 ingredient Grapefruit vodka cocktail- ready in minutes!

Once you have your syrup ready, all you need to do is add some to a shaker with a shot of vodka and some fresh squeeze grapefruit juice. Shake well, then pour over ice and top with club soda or sparkling mineral water. Garnish with a wedge or slice of grapefruit and enjoy!

Serving Suggestions

Want to make a big batch of these Grapefruit vodka cocktails for a crowd? You could easily make a big batch with some pre-squeezed grapefruit juice (or bottled juice), vodka and fennel syrup in a pitcher, and let your guests add ice and top with seltzer as they serve themselves!

Made this Grapefruit Vodka Cocktail recipe? Leave a review and rating below!

If you make my Fennel Grapefruit Vodka Cocktail, please be sure to leave me a comment! I would love to hear from you, and value your feedback! Lastly, if you make the recipe and love it, please tag me on Instagram! I love to see your photos!

Fennel Grapefruit Vodka Cocktail

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Fennel Grapefruit Vodka Cocktail

Prep Time10 mins
Total Time1 hr 10 mins
Course: cocktail
Keyword: fennel, grapefruit, vodka
Servings: 1


  • 1.5 oz vodka
  • 1/4 cup fresh squeezed ruby red grapefruit juice
  • 1.5 oz fennel simple syrup
  • top with club soda or sparkling mineral water 

Fennel Simple Syrup

  • 1/2 tbsp fennel seeds 
  • 1 cup water
  • 1 cup organic cane sugar or granulated sugar


  • Make the fennel simple syrup. Add the fennel seeds, sugar and water to a small saucepan. Bring to a boil, then reduce heat to medium and simmer for 5 minutes, stirring occasionally until sugar is fully dissolved.
    2. Once sugar is dissolved and syrup is slightly thickened, turn off heat and allow to cool to room temperature. Strain into a jar or airtight container and store in the refrigerator until ready to use. Makes about 1.5 cups, and keeps up to 2 weeks in refrigerator.
    3. Make the cocktail. Add simple syrup, vodka and grapefruit juice to a cocktail shaker or mason jar and shake well. Fill a highball glass with ice and pour mixture over. Top with club soda or sparkling mineral water and garnish with grapefruit slice. Make 1.

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Looking for more great cocktails? Why not try my Tropical Thunder Pineapple Cinnamon Paloma, Gin Honey Bee, Boozy Orange Dreamsicle, or my Citrus Mint Vodka Mule!