The “burnt pieces” in Pu'er raw tea are undesirable. However, this undesirability is not due to toxicity or harm to health but mainly affects the taste and appearance of the tea infusion. Theoretically, these “burnt pieces” can be avoided during the Pu'er tea production process; however, in practical application, they are almost impossible to avoid.
The “burnt pieces” in Pu'er raw tea are essentially scorched tea juice that sticks to the Iron wok and is not something dirty.
During the process of fixing the fresh leaves, a large amount of Water and tea juice overflow from the leaves, while the wok temperature is mostly above 200°C, which is very high. After several batches of fixing, a layer of tea juice forms on the surface of the iron wok, which is scorched black by the high heat and mixes with a small amount of the Pu'er tea material.
We mentioned earlier that theoretically, “burnt pieces” can be avoided, and the most direct method would be to carefully clean the iron wok after each batch of fixing and before processing the next batch. If the scorched tea juice on the iron wok is completely washed off, it is theoretically possible to prevent “burnt pieces” from mixing into the raw tea material.
However, in actual practice, this is not realistic. Throughout the entire tea mountain, no matter how expensive the material, almost no one cleans the iron wok after each batch of fixing before processing the next batch. In most cases, the wok is cleaned once a day, and during the busy Spring Tea season, a tea fixer will process around 20 batches in a large iron wok per day. There are also cases where the wok is cleaned after every five or ten batches, but regardless, it is difficult to completely avoid the production of “burnt pieces.” Some cheaper fresh leaves processed by machines may only have their woks cleaned every few days or even dozens of days, leading to more “burnt pieces” being produced.
Almost every tea farmer in the tea mountains has several large iron woks for fixing tea specifically made from their own tea gardens. Each round of fresh leaf picking has an interval, and before fixing each round, the fixing woks are meticulously cleaned, resulting in relatively fewer “burnt pieces.” Since most farmers only process their own tea garden's leaves, the resulting tea flavor is much purer.
There are also many tea processing facilities on the tea mountains that specialize in processing fresh leaves for others. Tea merchants from other regions purchase fresh leaves from farmers and transport them to these tea processing facilities to be fixed. During the busy spring tea season, these facilities often operate around the clock with people rotating shifts, and the cleaning of the iron woks is not as frequent or meticulous as at the farmers' homes.
A more noteworthy issue is that these contracted processing facilities do not solely process tea from a single mountain or brand but handle multiple mountains and brands. The quality of fresh leaves from different mountains and brands varies greatly. After fixing the leaves from one tea garden without cleaning the wok, and then immediately fixing leaves from another garden, there is a possibility of flavor contamination, affecting the purity of the tea flavor, especially for products that emphasize pure single-origin teas from specific mountains. This effect should not be overlooked.
“Burnt pieces” primarily appear in Pu'er raw tea, especially in loose tea, which is the raw material after fixing, kneading, and sun-Drying, where “burnt pieces” are most noticeable. After compression into cakes, bricks, and tuos, visible “burnt pieces” become fewer; after sorting, piling fermentation, and blending in ripe teas, “burnt pieces” are hardly seen.
Since “burnt pieces” are practically unavoidable under real-world conditions, meaning they will appear in varying amounts in Pu'er raw tea, how much is acceptable? We believe there are two standards:
One, they should not significantly affect the pure taste of the tea, meaning a burnt taste should not be clearly discernible;
Two, they should not significantly affect the cleanliness and appearance of the tea infusion. A small amount of “burnt pieces” is normal, due to the objective circumstances of production, but the quantity should not be so great as to make the tea infusion appear “very dirty.”
The presence of “burnt pieces” can reflect whether machine fixing or manual iron wok fixing was used, whether the tea was processed by a contracted facility or by the farmers themselves, and the frequency and hygiene of wok cleaning. Consumers can use these details to judge the quality of a tea.