Like most other Chinese green tea, Longjing tea leaves are roasted early in processing (after picking) to stop the natural oxidation process, which is a part of creating black and oolong teas. The actions of these enzymes are stopped by "firing" (heating in pans) or by steaming the leaves before they completely dry out. As is the case with other green teas (and white teas), Longjing tea leaves experience minimal oxidation. When steeped, the tea produces a yellow-green color. The tea contains vitamin C, amino acids, and, like most finer Chinese green teas, has one of the highest concentrations of catechins among teas.