The making of Black Tea is not a mystery. From the harvest, fresh leaves need to go through at least 9 stages of processing to become a black tea product. Compared to green tea, which has only 3 tea-making steps, black tea’s tea-making is a lot more complex.
Because green tea’s basic tea-making, many tea lovers think that whatever involved in making a green tea is also required in other teas.
This is usually correct. After all, the only important tea-making step in green tea is “kill-green/杀青”, a step that uses heat to terminate the fermentation of tea leaves. As we all know, different tea categories have different levels of fermentation. Since all tea categories have a level of fermentation (even 0% fermented), all teas should have a “kill-green” process.
Of course, there’re exceptions. For instance, white tea products don’t have a “kill-green” step because white tea products can be aged, and any attempt to “kill green” or stop the natural oxidization would ruin the aging process.
Surprisingly, black tea is another big tea category that doesn’t officially have a “kill-green”. In fact, you won’t find any official documents, national/industry standards that say black tea has a “kill-green” process.
To many tea lovers, this fact is a shocking. As a fully fermented tea, if black tea doesn’t have a “kill-green” that stops the fermentation, wouldn’t tea leaves become over-fermented?
The answer is YES. If we keep fermenting black tea leaves after they’re fully fermented, tea leaves would develop a large amount of substances that taste sour, or grow an unpleasant odor similar to the smell of an old stone cellar.
Therefore, black tea’s tea-making steps must have something that can stop tea leaves from over-fermenting. To find out how, we need to take a closer look at its tea-making.
Despite modern black tea doesn’t have a “kill-green”, the traditional tea-making of Lapsang Souchong/正山小种 (the first and original black tea, See our Blog 67 and Blog 68 for more) does have a “kill-green” step called “Guo Hong Guo/过红锅” (meaning: going through a red wok; wok: a pot-like utensil but with a round bottom).
“Guo Hong Guo/过红锅” refers to stirring and flipping tea leaves in a hot wok after the fermentation. This process looks exactly like “kill-green” in green tea. By going through this heating process, the active enzymes are suppressed and destroyed. As a result, the fermentation comes to a stop.
But, why is “Guo Hong Guo/过红锅” no longer needed in modern black tea?
To be honest, we do not have a definitive answer. Our tea makers’ speculation is that “Guo Hong Guo/过红锅” is a relatively simple and short process. To many tea makers, the real purpose of it is more about accelerating the drying of tea leaves in stead of “kill-green”.
In order words, despite ““Guo Hong Guo/过红锅” has the effect of “kill-green”, its true objective is to dry tea leaves.
Therefore, in official documents, “Guo Hong Guo/过红锅” is probably dismissed as a necessary tea-making step.
Also worth mentioning, modern black tea tea-making no longer uses traditional tools such as bamboo baskets. Bigger and more efficient machines, such as electric drying machine and roasting machine, have taken over the drying process. These machines can better provide a constant high temperature that effectively kills the enzyme activity while drying tea leaves.
Although modern black tea doesn’t officially have a “kill-green” process, the result of “kill-green” is still accomplished by other related tea-making activities.
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