The quality of black tea is determined by the ratio of theaflavin and thearubigin produced during the fermentation process. If fermentation is insufficient and the ratio of theaflavin is high, the color of the broth becomes close to a greenish orange, and it has a bitter and stimulating taste. If fermentation is over, the ratio of thearubigin increases, the color of the broth becomes brown, and the taste becomes bland, and the unique flavor and aroma of black tea disappears. Black tea with proper fermentation has a unique bitter and astringent taste that is in harmony, giving it a refreshing taste.Sannoru's black tea is a straight tea made only with tea leaves from Jeju, allowing you to enjoy the original bright color and fragrance of Jeju black tea.Black tea promotes blood circulation, acts as a diuretic, and is very helpful in excreting waste products accumulated in the body. It also has a warming property, so it plays a role in warming the body that has become cold in the cold winter.