Catechin

Have you ever tasted a "sour" flavor while savoring tea? What kinds of sour flavors can be found in tea? Why does tea have a "sour" taste? Which types of sourness are good, and which ones are not? Let’s explore these questions together! Wuyi Sourness Some high-quality Wuyi Rock Teas naturally develop “Wuyi Sourness” during their aging process. In the mid-19th century, Western tea scholars discovered "tannin" (catechin) in rock tea and isolated "Wuyi Acid." Later, it was confirmed that Wuyi Acid is a mixture of beneficial substances including gallic acid, oxalic acid, tannin, and quercetin. In 1847, Rolland isolated "Wuyi Acid" from Wuyi Rock Tea. In 1861, Hasewitz confirmed that Wuyi Acid is a mixture of gallic acid, oxalic acid, tannin, and quercetin. It's important to distinguish between the genuine Wuyi Sourness, which is "sour but not cloying," and the sour taste caused by processing errors, which can induce nausea. The latter might be referred to as "nauseating sourness." Therefore, one should not blindly pursue the Wuyi Sourness. As the saying goes: "Though Wuyi Sourness is good, don’t overindulge!" Therefore: Authentic Wuyi Sourness is good, while nauseating sourness is undesirable! Tieguanyin Sourness The false sourness in Tieguanyin, known locally…

Tea tasting is an art and a culture. A good cup of tea not only has a rich aroma and a sweet taste but also leaves a lasting impression. However, some teas can be bitter and astringent, affecting the tea-tasting experience. So, why are teas bitter and astringent? Let’s explore the scientific mysteries behind it today. Sources of Bitterness and Astringency in Tea The bitterness and astringency in tea mainly come from the following substances: Tea Polyphenols: Tea polyphenols are abundant antioxidants in tea with astringent properties. They bind with salivary proteins in the mouth, creating a bitter and astringent sensation. Different types of tea polyphenols have varying degrees of astringency. For example, catechin-type polyphenols have a stronger astringency, while flavonoid-type polyphenols have a milder astringency. Caffeine: Caffeine is a central nervous system stimulant with a bitter taste. Its content varies depending on the variety of tea, growing environment, and harvesting season. Generally, spring tea has lower caffeine content, while summer tea has higher caffeine content. Amino Acids: Amino acids in tea, such as theanine and glutamic acid, also contribute to a certain degree of bitterness. Factors Influencing Bitterness and Astringency in Tea In addition to the inherent components of…