Why does Dian Hong tea taste sour?

YuanJia131

The Dianhong I bought tastes sour when brewed. Is it spoiled
The term "sour" is highly prone to misunderstanding when applied to black tea. While Dian Hong (Yunnan Black Tea) indeed tends to exhibit a more pronounced sourness compared to many other black teas, this does not mean it inherently should taste sour. A properly brewed cup of Dian Hong may have a fleeting hint of acidity, which blends seamlessly with its sweetness and dissipates quickly. However, if you detect a sharp, persistent sourness clinging to the tongue, it is more likely a flaw in the production process rather than a characteristic of the tea variety.
Black tea is fully fermented, and the organic acid content in tea leaves is inherently higher than that in unfermented teas. Yunnan black tea uses the large-leaf variety of Yunnan, which has a high content of polyphenolic compounds. During the tea-making process, ester-type catechins hydrolyze to form organic acids. Some sources state it quite directly: Yunnan black tea is more prone to developing an astringent taste compared to Keemun black tea.

A Dian Hong tea with flawed craftsmanship or storage will fully reveal its sourness when brewed with boiling water. So if your Dian Hong tea turns sour "as soon as you use boiling water," it precisely indicates inherent issues with the tea leaves—the boiling water merely speaks the truth.
Conversely, hiding the acid by using low-temperature water is merely covering one's ears to block the sound of a bell. Dianhong tea, a large-leaf variety with plump and sturdy leaves, cannot release its internal substances if the water temperature is too low, resulting in a bland, watery taste. A good Dianhong tea fears no boiling water; if it does, its sourness often serves as its most honest confession.
A properly made Yunnan black tea may carry a faint hint of acidity, but it blends seamlessly with the sweetness, fleeting in nature, leaving a sweet and refreshing aftertaste. If the acidity is pronounced, sharp, lingers in the mouth, or even carries a musty, stale sensation, it signals poor craftsmanship or storage, not the authentic character of Yunnan black tea.
The simplest test: steep it in boiling water. If the sourness is completely forced out and impossible to avoid, that's a flaw in the tea leaves themselves; if it only briefly appears and then dissolves, it's simply the inherent, slightly sour base that makes Dian Hong a naturally robust black tea variety.
Labels can deceive, stories can deceive, but the moment the boiling water pours down, the acid in the cup won't lie to you.