Rinse the pandan leaves and lemongrass. Cut into shorter pieces; lightly bruise the lemongrass (optional, for more aroma). Add butterfly pea flowers, pandan, lemongrass, and rock sugar to a pot. Pour in the water.
Place over medium heat and bring to a boil.
Reduce to low heat and simmer for 15 minutes, until the tea turns a deep blue and smells fragrant. Turn off the heat and steep for another 3–5 minutes for a richer color.
Strain out the flowers and herbs. Let the tea cool, then transfer to a clean bottle and refrigerate.
Squeeze in lime or lemon before serving (or into each glass) to trigger the color change.
Stir and watch the tea turn from blue to purple. The citrus version will have a light, tangy flavor.
Video
Notes
Use fresh or dried ingredients – Fresh pandan and lemongrass give the best aroma, but dried versions work just as well for convenience.
Adjust color depth naturally – Add more butterfly pea flowers for a deeper blue color without making the flavor too strong.
Don’t skip the steeping step – Letting the tea steep after simmering helps intensify both the color and floral aroma.
Trigger the color change just before serving – Add lemon or lime at the end to get that vibrant blue-to-purple transformation.
Serve well-chilled for best flavor – Butterfly pea tea tastes most refreshing when fully chilled, especially on warm days.