Possible causes of black spots:

1. Kill-green equipment: Traditional Pu'er tea uses an iron wok for the kill-green process. Even if the wok is cleaned after each batch, black spots are unavoidable. It can be said that black spots exist in traditional Pu'er tea, only varying in quantity. Even specialized small-scale kill-green machines also produce black spots.

In terms of equipment, small-scale kill-green machines have difficulty controlling temperature (the total heating area is small, making it easy to heat up and cool down).

2. During the kill-green process: If stirring is not done in time, some leaves may become charred. In wok-frying, uneven distribution is inevitable.

3. Dry leaves falling into the wok: When the next batch is fried, these dry leaves are easily burnt into charred fragments.

The charred leaves produced during the kill-green process are crushed into small black particles during rolling, mixing into the tea strands. As you can imagine, even one or two charred leaves in a batch can cause many black spots in the entire batch.

Solutions: 1. Improve kill-green equipment: Use equipment with controllable and even temperature.

2. Improve the kill-green method: Replace traditional manual stirring with more balanced methods, such as mechanical flipping.

3. After the kill-green process and before rolling, use methods such as blowing air or sieving to remove charred fragments and burnt crumbs produced during the process.