The World from a Tea Plant's Eye - Part Two, by Michael Harney

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Continued from this morning...

Two of the most popular types of teas are green tea and black tea. Both come from the same leaf. The difference is that the green tea is kept green by steaming it immediately after plucking. To make black tea, a leaf is rolled enough to make it limp, so that the polyphenols within mix with an enzyme PPO (PolyPhenolOxidase), also released inside the leaf, and the green tea turns into black tea.

Why plants have these reactive substances within them, and why they keep them safely apart (until we rupture them) is still under study. One elegantly simple theory, property of Dr. Peter J. Davies, of Cornell University, suggests that when these two reactive substances coagulate, making tea in the bug belly! - the bug finds the tiny tea mix repellant, and it stops eating the leaf. Experts have unilaterally, in any case ruled out the old theory that polyphenols and its enzyme's natural role in the tea leaf was to give the Brits a brisk cuppa.

An inherent charm of oolong tea (and, more subtly, of black tea) is its lovely floral fragrance, which derives from at least two sources. One is the reaction between sugars in the leaves and the enzyme PVO (PrimeVerOsidase), which together produce the building block that morphs into various aromas. The other source of oolong's alluring floral fragrance and taste is the breakdown of the leaf's fatty acids into a variety of compounds, including Methyl Jasmonate (also found in Jasmine flowers). These, too, help defend a leaf against bugs. Again Dr. Davies: "It stimulates production of proteases that precipitate the digestive enzymes of the insects' guts, ruining their digestion and their lunch!" Thus they promptly cease and desist their tea leaf lunch. It follows, also, that the released aroma serves the same role as a flower's scent: to attract another insect or animal that might eat the offending bug, poisoned and paralyzed with insectile indigestion. There are as many compounds derived from these building blocks as there are indigenous types of invader bugs.

Nature is elegant. All that is needed to make the tea you like, exists in the green leaves. The components are in the tiny leaves to protect those leaves. We love to drink the byproducts of the plant's self defense. We express this love by carefully tending tea plants throughout the world!

A good oolong to try is  Fanciest Formosa Oolong. A black tea in the Chinese tradition is Panyong Congou, and on e from the British Legacy would be Assam.

Cheers!