What are the foams that floating on the surface of tea liquid?

A tea lover recently brewed some Oolong teas and found some foams floating on the liquor, then she asked Angle if this indicates that these Oolong teas are not clean?


Today our Teavivre will talk about this.

When we brew teas, the surface of tea liquid will produce some foams due to the oscillation of water and the foams actually is the tea saponin. As a natural glycoside compound, tea saponin is characterized by bitter and spicy flavor, insoluble in cold water showing sub-acidity with PH value between 5.6-5.7. It has strong foam ability without being affected by water quality. That’s why tea has foams always result in a better and mellower taste!

Glycoside compounds, like tea saponin, are widely distributed in plant species. They are also found heavily in garlic, Ginseng in a form called ginsenosides, or in Onions called Allyl Sulfide compounds.

According to the scientific research, tea saponin can help towards promoting antibacterial, anti-inflammation and easing pain. So they are harmless, but benefit to our body.


Therefore, it is safe for tea lovers to drink teas with foams on the surface.