The drink is made from strongly brewed Ceylon tea, or a locally grown landrace (traditional or semi-wild) version of Assam known as Bai Miang. Other ingredients may include added orange blossom water, star anise, crushed tamarind seed or red and yellow food coloring, and sometimes other spices as well.
The tea is sweetened with sugar and condensed milk and served chilled. Evaporated milk, coconut milk or whole milk is poured over the tea and ice before serving to add taste and creamy appearance. Condensed milk and sugar may also be mixed with the tea before it is poured over ice and then topped with evaporated milk. In Thai restaurants, it is served in a tall glass, but when sold from street and market stalls in Thailand it may be poured over the crushed ice in a plastic bag or tall plastic cups. It may also be made into a frappé at some vendors.
Although Thai tea is not the same as bubble tea, a Southeast and East Asian beverage that contains large tapioca pearls, Thai tea with tapioca pearls is a popular flavor of bubble tea.