Moldy tea is harmful to health and should not be consumed, we all know this. However, sometimes tea enthusiasts express difficulty in distinguishing between moldy tea, “golden flowers,” and “white frost.” What are the differences between moldy tea, “golden flowers,” and “white frost”?
Moldy Tea
Tea leaves that have gone moldy generally grow white fuzz and emit a musty smell. Severely moldy tea can become rotten and clump together, with green fuzz growing on top, and Pu'er tea may also develop black mold. However, some premium varieties such as Biluochun, Mao Feng, Yunwu tea, Dian Hong, Tuocha, Pu'er, and others, have white down on their leaves. This is due to the tea's tenderness and not the white fuzz that grows when tea has molded.
According to Academician Chen Zongmao of the Chinese Academy of Engineering and researcher at the Tea Research Institute of the Chinese Academy of Agricultural Sciences, tea becomes moldy due to contamination by Penicillium and Aspergillus, which can produce toxins like aflatoxin (classified as a Group 1 carcinogen by the International Agency for Research on Cancer of the World Health Organization, it is an extremely toxic substance). Aflatoxin is heat-resistant and cannot be eliminated through high-temperature cooking. It can destroy liver tissue in humans and animals, and in severe cases, can cause liver cancer or death. Therefore, drinking moldy tea may cause mild symptoms such as dizziness, blurred vision, and diarrhea, but in severe cases, it could lead to diseases of vital organs such as the liver and kidneys. Thus, moldy or deteriorated tea should not be consumed.
“Golden Flowers”
“Golden flowers” are a key process in the production of Fu brick tea (dark tea) that forms its unique qualities. By controlling certain technical parameters, the growth and reproduction of beneficial fungus Eurotium cristatum is promoted, producing golden closed sacs, commonly known as “golden flowers.” The more “golden flowers” there are in Fu brick tea, the better the quality, hence the saying, “Good tea bears golden flowers, and the presence of golden flowers indicates good tea quality.”
The color of “golden flowers” in Fu brick teas from different years changes over time: newly baked Fu brick tea contains a large number of golden granules resembling “mignonette.” As the tea ages, the golden flowers gradually shrink and turn white, and in some very old Fu brick teas, the golden flowers may no longer be visible, only faint white spots can be seen. Therefore, newer teas have abundant “golden flowers,” while older teas may have fewer or no visible “golden flowers.”
“White Frost”
“White frost” refers to a white, mold-like appearance on the surface of tea cakes, which is a natural result of fermentation specific to Pu'er tea cakes.
How to Distinguish Between Moldy Tea, “Golden Flowers,” and “White Frost”?
Aspergillus appears yellow and flaky, and under human manipulation, it can resemble “golden flowers,” making it difficult for the average person to tell them apart. The best method is to examine the appearance: mold is threadlike and distributed in patches, appearing yellow, usually found in one corner of the tea cake. In 14 to 21 days, the area covered by mold can reach 4 cm to 6 cm in diameter and be about 0.5 cm to 1 cm high. The moldy tea will feel sticky and the layers of leaves will not be distinct, and the tea will appear deep black. Moldy tea that has been dried and stored will have shriveled mold bodies, irregular shapes, and a brownish color.
In contrast, “golden flowers” typically appear inside tea cakes or bricks, as point-like particles, golden in color. When distributed on the surface of the tea, there may be clusters of several golden flowers, but each flower is distinct and the boundaries between them are clear. The differences between the two types of tea become apparent when brewed: moldy tea produces a dark black or dark brown, murky infusion with a strong, pungent, moldy odor. After 4 to 5 infusions, the tea's color becomes very light and remains murky. Tea with “golden flowers” tastes smoother and has a round, silky mouthfeel, along with a unique sweet fragrance from the golden flowers. Its infusion is bright red, clear, and remains flavorful and vibrant even after numerous infusions.
It is also challenging for most people to distinguish between “white frost” and white mold just by looking at the surface. The most obvious difference is that “white frost” appears only on the surface of the tea cake. If you open a tea cake and find white substances within, and if they have a heavy, damp, moldy smell or release steam upon opening, it is likely moldy tea rather than aged Pu'er.
