White tea, which you’re familiar with from a previous tea class, has simply been dried and is relatively unprocessed.
With black tea, the leaves are cut and then left to oxidise to develop a richer, deeper flavour. (It’s similar to what happens when a cut banana is left exposed to the air – it goes black).
And with green tea, the cut leaves are steamed to kill off the enzymes, stopping them from oxidising. This gives it a light, fresh taste.
Then halfway between a green tea and black tea, we have Oolong, which is semi-fermented. Right on the end of the tea-processing spectrum, we have Pu'erh – it’s oxidised twice and then left to age...