Accidentally took a workshop on this at a tea festival a number of years back.

Turns out the “fermenting” of tea is mostly self contained. Autolysis, I think might be the word?

If you recall that caffeine is an insecticide this makes sense. The caffeine is stored as a time bomb waiting for some insect to chew. Mastication mixes the caffeine crystals and the enzymes already present in the leaf, which then render it soluble and bang, dead insect. To process tea you just need to activate the enzymes the right amount at the right temperatures, and then dry the leaves before they can rot.

If you get a proper oolong loose leaf, and let it steep long enough, you will find what looks like whole leaves in your cup. Not unlike those little dinosaur sponges they sell to kids. Just add water.

Interesting, can you realistically get good results from that when growing it in mild climate like US or Europe? Indoor? Greenhouse?