A fine Pu'er Tea is hard to come by, from selecting the land, choosing the trees, to refining the leaves, every step must be strictly controlled to ensure quality. Among these steps, “killing the green” is a crucial part of the correct Pu'er tea production process, it's a demanding technique that consumes time and effort, impacting both the immediate drinking experience and the potential for aging. Common methods of “killing the green” in Pu'er tea include manual and machine-assisted processes.
The Meaning of “Killing the Green” in Pu'er Tea
The term “green” refers to fresh leaves. We often speak of “fresh tea,” referring to these raw leaves. “Killing the green” does not mean to kill the fresh leaves but rather to destroy their cellular structure, allowing the internal substances to rapidly transform under high heat, forming the unique qualities and flavors of different tea types.
In addition to the well-known manual process using large iron woks, there are now various methods such as pan-killing, roller-killing, and trough-killing. Regardless of the method used, the goal remains the same: to apply heat to quickly alter the structure and composition of the fresh leaves, accelerating their transformation and laying a solid foundation for producing high-quality tea.
The Temperature for “Killing the Green” in Pu'er Tea
When discussing “killing the green,” temperature control is essential, particularly for Pu'er teas that undergo natural post-fermentation. For Pu'er tea, a temperature of 80°C is ideal, with a maximum of 85°C. This temperature is sufficient to eliminate the undesirable grassy aroma while preserving the potential for post-fermentation.
Those who have witnessed the process may initially think that the surface temperature of the iron Wok exceeds 280°C, which is significantly higher than the recommended 80°C. However, this is a misunderstanding.
The surface temperature and the temperature of the fresh leaves are two different things. A surface temperature of over 280°C ensures that the temperature of the leaves reaches around 80°C. During the process, the tea maker alternates between flipping, tossing, covering, and shaking the leaves to dissipate excess heat. The 85°C threshold is critical, and the temperature is typically raised to this level within two to four minutes and maintained for an additional one to two minutes before gradually reducing the heat.
The Purpose of “Killing the Green” in Pu'er Tea
The purpose of “killing the green” in Pu'er tea is to inhibit enzymatic activity and slow down fermentation. This is done to ensure good aging potential. Pu'er tea emphasizes continuous post-fermentation during storage, and the enzymes that survive the “killing the green” and subsequent low-temperature drying maintain some biological activity, which is important for the tea's post-fermentation. Therefore, the quality of the “killing the green” directly affects the overall quality of the tea.