The vibrant blue tea that transforms into purple with a single drop

Gardening · Published 18 October 2026 Swipe more like this →

In short: Deep blue and strikingly beautiful, butterfly pea flower tea is a South East Asian staple that performs a chemical magic trick. By simply adjusting the pH level with an acidic ingredient, this caffeine-free infusion shifts from a vivid azure to a bright purple.

Derived from the Clitoria ternatea plant, a member of the Fabaceae family, butterfly pea flower tea has been brewed for centuries across most South East Asian countries. While it is a long-standing tradition in regions like Thailand and Vietnam, it has only recently gained global popularity through food blogging and travel media. In Thailand, a common preparation is nam dok anchan, a drink often served at spas or after dinner, sometimes mixed with honey and lemon.

The tea's most famous characteristic is its sensitivity to pH levels. When steeped in hot or warm water, the petals impart a deep blue tint, a property that has historically made the plant useful as a dye and a food coloring for dishes like the rice dish nasi kerabu. However, the color is chemically reactive. Adding an acid, such as lemon juice, shifts the tea toward purple; the more juice added, the deeper the shade. Conversely, mixing the tea with fuchsia roselle hibiscus leaves can result in a bright red color.

Beyond its visual spectacle, the tea is used in Ayurvedic traditions for its supposed medicinal properties. In modern mixology, the instantaneous color change is used for showmanship in cocktails, or even frozen into ice cubes to create a 'mood ring cocktail' that changes color as it melts. While not a supermarket staple, it is available via specialty retailers. The US Food and Drug Administration officially categorised butterfly pea flower extract as safe and not requiring certification on 2 September 2021.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

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