Research Report on White Tea

As one of China’s six traditional tea categories, white tea is renowned globally for its unique production process—no pan-frying or rolling—silvery grayish-green appearance, and cool, mild properties. Originating mainly from Fuding, Zhenghe, Jianyang, and Songxi in Fujian Province, it is classified into four varieties based on picking standards: Silver Needle, White Peony, Gongmei, and Shoumei. Cherished by overseas Chinese as a traditional beverage, white tea has also emerged as a global research focus due to its rich health benefits. This report systematically sorts out the core research areas, key findings of white tea based on existing academic studies, providing an objective reference for tea lovers and researchers.

I. Research on the History of White Tea

From the perspective of tea evolution, white tea is believed to be one of the earliest tea categories. The ancient practice of sun-drying tea leaves for storage is highly similar to modern white tea production techniques. In the Ming Dynasty, Tian Yiheng recorded in Notes on Boiling Spring Water that "sun-dried tea is superior, as it is close to nature," clearly affirming the natural drying process and excellent quality of white tea. This is the earliest surviving explicit record of white tea production and quality.

There are two mainstream academic views on the origin of white tea. On one hand, some argue that modern white tea originated in Shuiji, Jianyang, Fujian, created by local tea farmers in the mid-to-late 18th century. Initially made from Xiaocai Tea, it was commonly known as "Nankeng White." On the other hand, others hold that white tea production began in Fuding, later spreading to Shuiji and Zhenghe. Early Silver Needle was made from plump buds of Xiaocai Tea. After the discovery of the Fuding Dabai Tea variety in 1857, its thick buds and abundant down made it superior to Xiaocai Tea in both appearance and quality, gradually becoming the core raw material for Silver Needle.

The "white tea" mentioned in Emperor Huizong of Song’s Treatise on Tea actually refers to special tea tree varieties with albino leaves, processed similarly to green tea—not the white tea categorized among China’s six traditional teas. With the promotion of tea tree varieties, classifications like "Dabai (big white tea)," "Xiaobai (small white tea)," and "Shuixian White (narcissus white tea)" gradually formed. Varieties such as Fuding Dabai and Zhenghe Dabai now dominate white tea production, while the traditional Xiaocai Tea and Shuixian Tea are rarely used.

II. Research on White Tea Cultivation

White tea cultivation techniques are not significantly different from those of most green teas. Research mainly focuses on two directions: screening suitable varieties and formulating standardized planting norms. Through long-term practice and research, seven varieties are generally recognized as suitable for white tea production, including Fuding Dabai Tea, Zhenghe Dabai Tea, Fuding Dahao Tea, Fu’an Dabai Tea, and Fuyun No.6. These varieties have stable biological characteristics and can fully reflect the flavor characteristics of white tea.

The White Tea Standard System, issued by Fujian Provincial Bureau of Quality and Technical Supervision in 2001, systematically regulates white tea planting, covering sexual propagation of tea trees, cutting seedling raising, tea garden establishment, daily management, and transformation of low-yield tea gardens. It provides technical support for large-scale production of high-quality white tea. In recent years, ecological tea garden construction has become a new research hotspot. Researchers emphasize the ecological balance of tea garden environments, improving the natural quality of fresh leaves by optimizing soil conditions and controlling pests and diseases.

Different tea varieties vary in bud-leaf morphology, down content, and biochemical composition, directly affecting the flavor of the final product. For example, Fuding Dabai Tea has plump buds and dense down, making it suitable for producing Silver Needle. Zhenghe Dabai Tea has a longer growth cycle and abundant internal substances, resulting in a mellow and brew-resistant white tea.

III. Research on White Tea Picking and Fresh Leaf Quality

1. Research on Picking Techniques

Picking is a key link determining the quality of white tea raw materials. Studies show that spring tea has the best quality, accounting for approximately 50% of the annual output. The first one or two rounds of picked buds and leaves are most suitable for making Silver Needle. Picking must follow the principle of "balancing picking and nurturing," adjusting the frequency and standards according to tea tree variety, age, season, and growth status to avoid over-picking affecting tree growth.

Both traditional experience and modern standards emphasize selecting pest-free, mechanically undamaged, and intact buds and leaves for picking. Silver Needle requires plump single buds; White Peony uses one bud with one or two leaves; Gongmei and Shoumei adopt one bud with two or three leaves and young shoots. The picking standards for different varieties directly determine the grade and flavor of the finished tea.

2. Research on Fresh Leaf Quality

The quality of fresh leaves directly affects the final taste and nutritional composition of white tea. Studies have found that the amino acid content in down is significantly higher than in the tea leaves themselves, which is an important source of the fresh and smooth taste of white tea. Fresh leaves of different varieties vary in chlorophyll, carotene, and lutein content. These components undergo transformation during processing, influencing the color of the tea liquor.

The White Tea Standard System specifies the quality grades, yield rates, and acceptance and piling requirements for fresh white tea leaves, providing quantitative standards for raw material selection. For example, fresh leaves of Fuyun No.7 have a high content of ester-type catechins. During processing, the operation rhythm must be controlled to avoid red discoloration, which would affect tea quality. Indicators such as the freshness and moisture content of fresh leaves also need strict control to ensure the smooth progress of subsequent processing.

IV. Research on White Tea Processing

1. Research on Processing Techniques

The core processing techniques of white tea are withering and drying. The absence of pan-frying and rolling preserves the natural properties of the tea leaves. Traditional processing mainly relies on natural withering, allowing fresh leaves to lose moisture slowly in a well-ventilated, cool environment. Modern techniques such as hot air withering and temperature-controlled withering have been developed to better control environmental temperature and humidity, improving quality stability.

In the primary processing stage, controlling withering time, temperature, and humidity is crucial. Studies have summarized specific technical indicators, such as the timing of combining sieves, the appearance during drying, and weight loss rate, to ensure moderate transformation of tea leaves during withering. Refined processing includes sorting, sieving, and drying steps to remove impurities and broken leaves, adjusting the tea moisture content to below 7% for easy storage.

New-process white tea has been improved on the basis of traditional techniques, optimizing tea appearance and flavor by adjusting processing parameters. However, it is still necessary to balance the tightness of the appearance with the inherent flavor, avoiding excessive oxidation that would damage the unique quality of white tea. Currently, deep-processed white tea products (such as cosmetics and daily necessities) have gradually entered the market, but relevant academic research remains scarce.

2. Changes in Components During Processing

The quality formation of white tea is closely related to biochemical changes during processing, with core research focusing on the following aspects:

• Enzyme activity changes: In the early stage of withering, water loss from buds and leaves increases cell permeability, enhancing the activity of polyphenol oxidase and peroxidase. Natural withering shows two activity peaks at 30 hours and 54 hours, while temperature-controlled withering has three peaks. In the later stage, enzyme activity weakens due to product inhibition and protein autolysis, and becomes completely inactive after drying.
• Pigment changes: During temperature-controlled withering, the total chlorophyll content decreases by 7.7%, with chlorophyll a showing the largest decline. In the drying stage, both chlorophyll a and b further decrease, with a greater reduction in oven-dried leaves than air-dried ones. Carotene, lutein, and polyphenol oxidation products jointly participate in the formation of white tea’s color, ultimately presenting its typical silvery grayish-green appearance.
• Polyphenolic substances: During natural withering, soluble polyphenolic compounds decrease by approximately 36%, and the total catechin content decreases by about 49%. Among them, L-GC, D,L-GC, and L-EGCG show the most significant declines, which is an important reason for the low bitterness of white tea.
• Amino acids: The overall trend is increasing, but in the middle stage of withering, amino acid content decreases temporarily due to the reaction between amino acids and o-quinones to form aldehydes. The total amino acid content of some varieties can nearly double after processing. Theanine, as the main flavor amino acid, its content change directly affects the freshness of the tea liquor.
• Other substances: During natural withering, the dry matter content decreases by 4.2%-4.5% due to respiratory consumption, and total sugar decreases by more than half. Low-boiling aromatic substances decrease in the early stage, increase in the middle stage, and decrease again in the later stage, while medium and high-boiling aromatic components increase significantly—several times or even dozens of times—forming the unique aroma profile of white tea.

V. Research on the Health Benefits of White Tea

Numerous studies have confirmed that white tea’s simple processing technology can maximize the retention of natural functional components, endowing it with various health benefits:

• Outstanding antioxidant capacity: ESR measurements show that white tea has the lowest free radical content among all tea categories. This is closely related to the low processing temperature and mild oxidation of polyphenolic substances. The flavonoid content increases by 16.2 times compared to fresh leaves, exhibiting significant antioxidant and anti-aging effects.
• Clear antibacterial effects: Studies have shown that white tea extracts have a good inhibitory effect on pathogenic bacteria such as Salmonella, with better bactericidal effects than green tea.
• Promotion of physiological health: It can significantly increase the serum EPO level of experimental animals, promote the production of CSFs by spleen lymphocytes, and play a positive role in erythropoiesis and cell lifespan extension. Cool in nature, it has traditionally been used to reduce fever, relieve internal heat, and alleviate summer heat, making it suitable for people with warm constitutions.

These research findings provide scientific evidence for the health value of white tea, gaining it more attention and recognition worldwide as a traditional beverage.