Gather a bunch of Pandan leaves according on how much aromatic you want your juice and tie them into a knot so that it will be easier to remove from water later.
Fill in 2/3 warm water in a large pot.
Drop the knot of pandan leaves into the water then bring to boil .
Let the leaves boil for 10 minutes.
Reduce the heat to simmer and cover the pot. Simmer the leaves for another 10 minutes until the leaves soften and the water turns green.
Remove the leaves from the juice. Let the juice cool to room temperature and transfer it to an air-tight container.
Store the juice in the refrigerator up to 7 days.