Due to the impact of stems on the aesthetics of Tea leaves, people often believe that tea containing stems is of inferior quality. In fact, the stem plays a very important role in the production and brewing of tea, influencing the concentration, taste, and quality! Tea with stems is more enduring when brewed; if one only picks the ‘leaves' without the ‘stems,' both the enjoyment and effectiveness are significantly reduced.

The Role of Stems in Production

In the processing of Tieguanyin tea, after picking, the stems and leaves exchange moisture, promoting fermentation. Therefore, Tieguanyin is always harvested with its branches and then processed by removing the stems afterward.

During the shaking process: the moisture from the stems flows to the leaf surface, reviving the tea leaves. At the same time, the edges of the leaves are broken through friction with the shaking tools, forming red edges through oxidation, accelerating fermentation.

The fixing process in the production of Tieguanyin is a critical step in shaping the quality characteristics of the tea. Fixation is an important stage of tea fermentation, during which the cells on the green tea leaf surfaces remain active. Simultaneously, the leaf surface undergoes transpiration, emitting large amounts of water and carrying away the heat generated by fermentation. This creates a pull that allows the moisture in the stems to be transported through the xylem from the veins to the mesophyll tissues, keeping the leaves from drying out and maintaining the fermentation and oxidation processes of the tea.

Additionally, the vascular bundles in the stems are the primary conduits for nutrients and aroma. Most of the substances they contain are water-soluble. During the processing of the tea, the aroma travels from the stems to the leaves with the evaporation of water, and these substances combine with the effective substances in the leaves to form richer and more concentrated fragrances. Therefore, having an appropriate amount of stem is necessary to produce fragrant and flavorful tea. If the stem's regulation of moisture in the leaves were lost, the fermentation process of Tieguanyin would be significantly shortened, making it difficult to achieve proper fermentation of the green tea leaves and challenging to produce the unique color, aroma, and taste of Oolong Tea.

Rich Inner Substances in the Stems

The amino acid content in tender stems is much higher than in buds and leaves, especially Theanine, which is 1-3 times higher in tender stems. This is mainly because theanine is synthesized in the roots and then transported through the xylem to the above-ground parts of the plant. Some of it participates in the nitrogen metabolism of the tea plant as glutamic acid, while the rest accumulates in the new shoots. Thus, the amino acid (especially theanine) content is high in tender stems. Additionally, as the nutrient-conducting organ of fresh leaves, stems contain a higher proportion of sugars. Fresh tea leaves contain many types of sugars, and mature leaves and stems have almost all types of sugars at levels higher than those in young buds and leaves.

Amino acids are an essential flavor component, playing a leading role in the fresh and sweet taste of the tea infusion and having a significant influence on the formation of tea aroma.

The main sources of tea aroma substances are found in the stems and the main veins of young leaves, with the aroma decreasing from the first to the third leaf. The aroma content in the stems is the highest.

The Benefits of Stems

Stems contain a large amount of tea polysaccharides, lignin, and cellulose, which can promote gastrointestinal motility, assist in food digestion, and lower blood sugar levels. Many people also use tea stems as an important ingredient in dietary therapy for diabetes. Experts indicate that the nutrition and essence of tea are in the stems and leaves. Consuming 6 grams of tea stems daily can effectively prevent aging and radiation exposure, and to some extent, tea stems also have disease-preventing effects. Therefore, there is no need to be overly concerned about tea stems; for various types of tea, stems can contribute to enhancing quality to a certain extent.