Oil in tea
Sometimes when brewing tea, you can notice small oily spots floating on the surface of the brewed tea. This can happen when brewing tea which has been roasted, for example, in a large pan or wok.
Oil is obtained from tea tree seeds and applied to the pan so that the leaves can slide during roasting, and also that the leaves do not burn. Tea seed oil solidifies at room temperature, tea makers form them into sticks and apply as a thin layer in the pan to roast the tea leaves.
The presence of oil spots does in tea doesn't indicate good or bad quality of tea, but only indicates that the leaves were fried in a pan, and not steamed. This method is more labor intensive than using steam engines, as it is usually done by hand. Plus, pan-fried leaves give a more toasted flavor compared to steamed ones.