Pu'er is the tea that comes to mind when talking about fermented teas. It's an outstanding starting point for tea-aficionados, and so we'll discuss Pu'er as a way to tackle important concepts of how to enjoy and understand this complex processing.
For Pu'er tea, there are two major types
Oxidation is started with rolling/bruising. By bruising we mean damaging the cell walls in order to expose the insides of the cellular structure to initiate that oxidation process.
Some use baskets and some use machines similar to a coffee roaster (but no applied heat), and roll it around, but damaging the stems as it rolls around.
We’re talking percentage of oxidation, as in “what percent oxidized.” Our Baozhong is its own type of thing between green and black tea levels of oxidations. It can be as low as 10% but usual 20-80 or 90%.
To stop oxidation (or denature), leaves are baked to roughly 150° F.
Dried on racks to ensure uniform drying and time of drying.
For Sheng-- you want to age this to develop the flavors (mellows as it gets older). If you brew it early in its life, you’ll want to brew it cooler than you typically would. They won’t go bad and get stale as other teas or coffees would. You can age Pu'er to develop flavor, but keep it in the puck-form (unbroken) if you don't plan on drinking it within five years. Leave it wrapped in its paper, and why not keep it in the box from whence it came.
You don’t have to worry about this being air-tight in storage, but light is something you’ll want to be wary of as it sits over long stretches.
If you’re willing to invest, you can find teas from the 1930’s and 1940’s.
Shou teas will brew more earthy, dank, full right from the start.