Air is used for several purposes in tea manufacturing: 1. To remove moisture during withering at relatively low temperatures.
2. To supply oxygen to the leaf during fermentation.
3. To control the temperature of leaf during fermentation
4. To supply heat to the fermented tea for enzyme inactivation and to remove moisture during drying, at relatively higher temperatures.
If you do the math, 4.5 tonnes yeilds 1 tonne ~ 22.22%...
I don't know about you, but it makes me think twice about how much I should appreciate each cup of tea. The next time I take a sip of my tea I will make sure I savor the moment and pay homage to all the work required in making it to my cup and into my belly.