The Tea Leaf and Its Transformation

A fresh tea leaf tastes bitter and astringent, and not much else. This is a reflection of the fact that its major chemical component, even more abundant than its structural materials, is a host of bitter and astringent phenolic substances whose purpose is to make the leaf unattractive to animals. And its aromatic molecules are locked up in nonvolatile combinations with sugar molecules. Green tea retains many of the qualities of the fresh leaf. But the key to making oolong and black teas is encouraging the leaf’s own enzymes to transform these austere defensive materials into very different, delightful molecules.