Someone once said that magic is just science we don’t understand. We’d like to amend that by saying that sometimes, even when we understand science, it can still be thoroughly magical. This beautiful butterfly pea flower syrup cocktail changes its color from deep blue to stunning violet. We know it’s a chemical reaction, but we still marvel at its supernatural transformation.
what are butterfly pea flowers?
The butterfly pea flower is a legume with cobalt blue blossoms native to Southeast Asia, and is scientifically known as Clitoria ternatea (yes, it was named by a 17th century male botanist, of course). They’re also known as Asian pigeonwings, blue butterfly pea or blue ternate flower. Its peas are edible, but it’s more known for its flowers than its fruit.
Butterfly pea is used in its local region as a tea, and a natural food dye, and globally, and certainly in our house, as a cocktail ingredient. Its blue color is a result of anthocyanins, chemicals present in all red and purple foods (including berries, red cabbage and dark-colored carrots). These plant pigments change their color when they go into solution with a low pH.
Which means, in laymen’s terms, if you add anything acidic (like lemon juice) to a butterfly pea flower tea or tincture, it will transform from deep blue to vibrant magenta. Empress 1908’s Indigo Gin is colored with this ingredient, which we’ve used to great success in other drinks. (We don’t use it here, for obvious reasons.)
You can find butterfly pea as whole dried flowers, or ground in tea bags. Either will work here, but the whole flowers are more cost effective. You don’t need a lot to color the syrup. Of course you can use the syrup in lots of different drinks (a rum-based mojito with this syrup would be fab). You could also use it in non-alcoholic drinks as the sweetener for a lemonade or summer tonic.
By itself, butterfly pea flower flavor is very mild, like a light green tea or matcha, so it needs to be mixed with other ingredients to make it more interesting. Note that anything with a low pH will cause the color change (citrus fruit, tonic water, white or sparkling wine will all work).
The final color of the butterfly pea flower cocktail will vary, depending on how much acid you add to the mix. You can keep the cocktail blue by not adding the lemon juice, or make it pinker by adding more acidic ingredients.
If you want a very red color, you can add some hibiscus flowers to the syrup but note that hibiscus has a very tart, almost berry flavor. It’s delicious, but you might not want to add as much lemon juice.
Butterfly pea simple syrup
This is a standard simple syrup, so uses equal parts of sugar to water. To make the butterfly pea flower syrup, you don’t need a lot of flowers, about a loosely packed 1/4 cup (about 7 grams), or 4 tea bags.
Once you combine the sugar, water and flowers, bring the solution up to a boil, then lower the heat to a simmer and let it lightly bubble for about 5 minutes or so. Turn off the heat and allow the syrup to cool to room temperature before you strain it. Add it to a clean glass jar and it will keep in the refrigerator for a few weeks.
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Make the cocktail
You could make this cocktail with vodka, if you prefer. Since the syrup is very lightly flavored, we think it benefits from the botanical flavors of a good gin. Our favorite for this drink is Plymouth, which is a London Dry gin. London Dry Gin is a style of gin that uses juniper as its predominant flavor and cannot contain added sugar. The other botanicals should balance out the juniper, often with coriander seed, citrus peel, and orris root.
Next, we add St-Germain, which is the original French elderflower liqueur. (We recently realized it was only created in 2007, which makes us wonder, what the hell were we drinking before that?) In keeping with our floral theme for this cocktail, St-Germain has a delicate, sweet flavor, with notes of peach, pear, and citrus. We grow elderflowers and love making drinks when they’re in bloom, which usually happens in mid-June.
Of course other elderflower liqueurs are now available. Fiorente, Bols, and The Bitter Truth are all great options and you may have your favorite. Each has their own distinct flavor, but any will work in this drink.
Then add the Butterfly Pea Flower syrup. We found 1/2-ounce to be perfect for our taste, but if you like a sweeter drink, you could step it up to 3/4 or 1 oz.
It’s the lemon juice that turns the mixture from blue to violet, and it’s so fun to watch it happen. Half an ounce is enough to give the drink a refreshing tartness. The final color of the drink will vary slightly, depending on the strength of your syrup and the acidity level of your lemons.
Several dashes of grapefruit bitters add depth and complexity. We tried Angostura bitters first, since they are the most common, but found the cinnamon, clove, and cardamom flavors too rich for this delicate drink. Lemon bitters would also be a good choice.
Next, add ice to the shaker and shake vigorously for 15 to 20 seconds. You not only want to make the drink cold, you’re also slightly diluting it.
Serve the Drink
Double strain the drink into a coupe (we pre-strained our lemon juice), and if you like, top it with a splash of soda water, or even better, prosecco or champagne.
Garnish with a lemon twist, and if you have one available, a little sprig of elderflower.
We recently got an atomizer, which sprays a very fine mist over the top of a drink. We loved the result from a small spritz of absinthe. More for the aroma than flavor, absinthe has botanical notes of anise, fennel, and wormwood, which complements the floral gin. You could leave this out, but it does add a sophisticated touch.
You may think the colorful transformation of a chameleon or a mood ring is amazing, but we’ll save our applause for this drink. The Social Butterfly: a butterfly pea flower cocktail that makes us believe in magic again.
The Social Butterfly (a butterfly pea flower cocktail)
Ingredients
Butterfly Pea Flower Simple Syrup:
- 1 cup water
- 1 cup granulated sugar
- 1/4 cup loosely packed fresh or dried butterfly pea flowers about 7g, or 4 tea bags
Cocktail:
- 2 oz dry gin or vodka
- 3/4 oz Elderflower Liqueur like St-Germain
- 1/2 oz butterfly pea flower simple syrup
- 1/2 oz fresh lemon juice
- 3 to 4 dashes grapefruit or lemon bitters or any bitters will work
- Top with a splash of sparkling water or Prosecco
- Optional Spritz with atomized absinthe
Garnish:
- Lemon twist
- Elderflower blossom
Instructions
To make the syrup
- Add water, sugar and butterfly pea flowers to a small saucepan set over medium-high heat. Bring to a boil and lower the heat to a simmer. Simmer for 5 minutes, turn off the heat and allow the liquid to cool before straining into a clean jar with an airtight lid. Keep refrigerated until ready to use. Will keep for several weeks in the refrigerator.
For the cocktail
- Add all the ingredients except for the Prosecco to a cocktail shaker and fill with ice. Shake vigorously for 20 seconds and double strain into a stemmed cocktail glass. Top with a splash of Prosecco or sparkling water, and spritz with absinthe, if desired.