Shaqing
Definition
The Chinese term for kill-green, the heat-fixing step that deactivates oxidative enzymes in fresh tea leaves. It is performed by pan-firing, steaming, baking, or tumbling depending on the tea style.
Why it matters
Shaqing, literally "killing the green," is the moment that defines what kind of tea a fresh leaf will become. By rapidly raising leaf temperature above roughly 70 to 80 degrees Celsius, processors denature polyphenol oxidase and peroxidase, the enzymes responsible for oxidative browning, locking in the green character of the leaf. For most Chinese green teas, shaqing is done by pan-firing in a hot wok or rotary cylinder, which also begins to develop nutty, toasty aromas. Japanese producers use steam (jousei) instead, preserving a fresher, more vegetal character. White teas largely skip shaqing, while oolongs receive a partial shaqing after the oxidation/bruising phase to halt further enzymatic activity. Timing and intensity of shaqing have an outsized influence on aroma, color, and shelf life. Too little and the tea will brown and dull; too much and the leaf scorches, losing fragrance and developing harsh notes.