Brew the Tea: Bring water to a boil in a small pot. Once it comes to a boil, turn off the heat. Add the Thai tea mix and sugar and stir until the sugar is dissolved.1
Strain the Tea: Pour the tea mixture through your tea sock filter to remove the tea leaves and other fine particle residue. Place the strained tea in the refrigerator until it is completely chilled.2, 3
Add Lime Juice and Serve: Add freshly squeezed lime juice to the cool tea.4 Stir to thoroughly incorporate. Pour the Thai Lime Tea over a glassful of ice. Serve immediately and enjoy!
Notes
You don't want to leave the tea to steep for very long, as it will become stronger and more bitter the longer it steeps. This is different from Cha Yen, where you want a very strong tea so that it doesn't become too dilute once milk is added.
If you're in a hurry, you could alternatively add some ice to the tea to help it cool faster. Just be aware that adding ice will dilute the tea flavor.
You can save the sweetened chilled Thai tea in the refrigerator like this. Before you're ready to serve the drink, you can add the lime juice for maximal freshness.
The tea needs to be cool when you're adding the lime juice, as heat breaks down lime juice and makes it become more bitter and cloudy.