
Slice ginger into 4 slices and use a pestle or something heavy to slightly bruise them. Peel and discard the outer layer of lemongrass. Cut each stalk in half crosswise and use a pestle or something heavy to bruise them.
Add water to a small pot and bring to a boil. Add ginger slices and lower the heat to a simmer. Cover the pot and simmer for about 10 minutes.
After 10 minutes, add lemongrass stalks. Cover the pot and continue to simmer gently for another 5-7 minutes.
Turn off the heat and remove the pot from the stove. Let the tea steep for another 5-10 minutes in the pot with the lid still on. You can even steep it longer if you prefer a stronger tea. The tea will also look darker when you steep it longer.
To serve hot: pour the tea into serving glasses. You can decorate each glass with a slice of ginger and a lemongrass stalk that you have just simmered.
To serve cold: let the tea cool down in the pot and then chill it in the refrigerator before drinking.
You can keep the tea in an airtight bottle or container in the refrigerator for up to 2 days. It can be reheated easily in the microwave.