Why does tea foam?

The foam that forms on top of tea is caused by the interaction between the air, the water, and the chemicals present in the tea leaves. The foam consists of tiny bubbles that form when air is trapped between the water and the tea leaves. The chemicals in the tea leaves, such as caffeine and tannins, stabilize these bubbles and prevent them from popping. The amount of foam that forms depends on the type of tea, the temperature of the water, and the brewing time.