Tannins are also studied in ancient times. Its astringent nature is found in plants and trees. Looking at the leaves, bark, fruits and the like, it often contains tannins. Its color may be dark or light, depending on the origin.

Taste it, the properties of tannins can coagulate proteins. If tannins are encountered with animal skins, the skin is firm and tough, and can be used for leather. This is also a wonderful use for tanning. And tannins are also found in tea soup. The astringent taste of tea may exist due to tannins. However, moderate tannins increase the charm of tea, making the tea taste more mellow and long.

It is also used in medicine, and tannins also have their functions. It can restrain sores and close the mouth, stop bleeding and calm pain. Doctors in ancient times often used herbs containing tannins to treat bleeding from gold sores and ulcers that did not close. Cover tannins can coagulate local proteins and form a protective film to resist external evil and promote muscle growth and healing.

Although tannins are invisible, they are used in daily use and medicine. Only by observing their properties and studying their uses can we know the wonders of good fortune, and each thing has its own suitability.