Our ancestors began paying attention to the mysterious sensation of "sweet aftertaste." Good tea often carries this "sweet aftertaste," and its intensity and persistence are frequently used as indicators to judge the quality of tea. In actual experience, the sweet aftertaste is often linked with salivation. This is a relatively mysterious experience, but it is undeniable that the sweet aftertaste brings us a pleasant sensation.

Compared to the sweetness that appears immediately upon entering the mouth, this "sweetness after bitterness" has a more dramatic aftertaste and is more often associated with the quality of good tea.

Sweetness after bitterness—it seems as if the sweetness is born from the bitterness, but the reality might not be so.

Usually, when we drink tea, the first thing we perceive is bitterness, because of substances like theine. So, do these bitter substances numb our tongue's sensations, thereby increasing our sensitivity to sweetness? This is our common understanding, but the truth is definitely not so! If you try eating a bitter medicine like quinine, you will find that your mouth only tastes bitter forever; even drinking water feels bitter.

In fact, sweet substances already exist in the tea soup itself—namely, sugars or amino acids. It's just that our tongue is more sensitive to bitterness; we first taste theine and tea polyphenols, and only afterwards do we taste the sweetness.

 

 

Furthermore, the sweet aftertaste is accompanied by a salivation effect, which simply means increasing the flow rate of saliva.

Role of organic acids:

Organic acids in tea stimulate the salivary glands to secrete, producing the sensation of "salivation and sweet aftertaste." Tea leaves contain various types of organic acids, accounting for about 3% of the dry matter. Most organic acids in tea are free organic acids, such as malic acid, citric acid, succinic acid, oxalic acid, etc. Other organic acids are also formed during the tea processing. During the withering and fermentation processes of tea leaves, the content of organic acids increases.

Role of tea polyphenols:

Besides bitterness, tea polyphenols also have a special astringent taste. A family of proline-rich proteins (PRPs) has been found in human saliva. These proteins have moisturizing and lubricating effects, but tea polyphenols can alter their properties, forming complexes, thereby making the oral epidermis feel the loss of lubrication—that is, the astringent taste. This astringency, like sourness, can promote the flow rate of saliva, giving us the sensation of "salivation."

Additionally, why does spring tea have a better sweet aftertaste effect and is more highly regarded?

The most convincing view is that because spring tea leaves grow after accumulating nutrients throughout the winter, these leaves accumulate sufficient sugars and amino acids. As for summer tea, firstly, there is more rainfall, and the leaves have a higher water content; secondly, the proportion of sugars and amino acids is relatively smaller, so its flavor naturally diminishes, with little sweet aftertaste.