By Jason Dalrymple
Not many people realize that Green, White, Oolong, Black and Pu’Erh teas all come from one plant. It seems hard to imagine this is true when each type of tea tastes so much different from the others. The differences in taste, color, smell, and appearance come from the different processing techniques that make each tea unique although the main difference in each tea is the amount of oxidation it goes through.
Oxidation happens when the enzymes in the leaf are exposed to oxygen in the air after the cells of the leaf are broken in the rolling process. Many people are familiar with oxidation and may not even know it: when you bite into an apple and it turns brown, when the leaves fall in the autumn and turn brown as well; these are both examples of oxidation. The enzymes that are released initiate the oxidation process and the more the leaf is handled, crushed, and curled, the more quickly it will change color. Oxidation is stopped by heating the leaves, or firing them, and when the enzymes are heated the oxidation process winds down and is no longer sustained. Here’s a quick guide to the oxidation levels in each of the five teas:
White tea: Completely air dried, unprocessed and no oxidation
Green tea: (Chinese) Pan-fired to stop oxidation completely before it starts
(Japanese) Steamed to stop oxidation completely before it starts
Oolong tea: Partially oxidized
Pu’erh tea: Can be oxidized or non-oxidized and aged and fermented