Butterfly pea flower tea changes from blue to pink—naturally—when you add lemon juice. Here's the science behind how this magical brew works.

You've heard of green tea, black tea and white tea. But a blue tea that changes color-naturally? Now that's something you've got to see.

The secret's in the tea leaves. While "blue tea" is also another name for oolong (an intermediary between green and black tea, that brews up orangey-red), the now-trending color-changing tea is made from the flower of the blue butterfly pea, a plant common to Southeast Asia. The sun-dried flowers can be used just as you would any other tea leaves. The difference: the blue butterfly pea flowers are naturally blue because they contain flavonoids, antioxidant pigment compounds that protect the petals from UV rays. When you add hot water, the flowers' flavonoids dissolve and a beautiful blue color develops in your cup: #bluetea, anyone? In fact, it's so colorful that it's hard to believe there isn't anything artificial in it. It's like magic.

And the magic doesn't stop there. Add a few drops of lemon juice and the color changes to a bright purple. How? Turns out it's more science than magic: Blue tea is a natural pH indicator, meaning it changes color when it encounters an acid or a base. The lemon's citric acid lowers the pH of the drink: presto, purple!

Drinking green, black, red and other teas has been linked with multiple health benefits, from lower stroke risk to improved heart health. Is blue tea healthy too? In Thailand, the flowers have traditionally been used for medicinal purposes as well as for tea and cooking, and emerging research links them with protection from some diabetic complications as well as age-related cognitive impairment. Their blue color is a clue. Like blueberries, grapes and other blue and purple foods, the flowers get their color from anthocyanins, specific flavonoids credited with antioxidant and anti-inflammatory powers. Researchers note, though, that these compounds don't have high bioavailability, and absorption may be lowered further by interaction with other foods (e.g., milk in your tea).

So maybe it's not a superfood, but blue tea is caffeine-free and can be a fun way to spice up your tea-drinking routine. Think outside the teapot, too: add some color to your next cocktail party (purple martinis?) or even to your cooking (infuse the cooking water to make fun blue rice or pasta).

Want to try it for yourself? You can order the tea online from Amazon and other online retailers.

Watch How to Make Color-Changing Lemonade Slushies