Tea Fundamentals
Tea Fundamentals
One Plant,
Two Teas
Green tea and black tea could not taste more different — and yet they begin as exactly the same leaf.
Same leaf, different journey
Every true tea — green, black, white, oolong, pu-erh — comes from a single plant: Camellia sinensis. What separates a grassy Japanese sencha from a malty Assam breakfast blend is not the plant itself, but what happens to the leaf after it is picked.
Green Tea
Shortly after picking, the leaf is heated — steamed in Japan, pan-fired in China — to stop any further change. The leaf stays green, the flavour stays fresh.
- Oxidation
- None (0%)
- Flavour character
- Grassy, vegetal, sweet
- Colour in the cup
- Pale gold to jade green
Black Tea
The same leaf is withered, rolled, and left to oxidise fully before being dried. The chlorophyll breaks down, the flavour deepens, and the liquor turns amber to dark brown.
- Oxidation
- Full (100%)
- Flavour character
- Malty, bold, brisk
- Colour in the cup
- Amber to deep copper
It starts with Camellia sinensis
The tea plant is an evergreen shrub native to southwest China and northeast India. Left to grow wild it becomes a tree; cultivated for tea production it is kept low and bushy so the young leaves — called the flush — can be hand-picked easily. The same plant has been cultivated for thousands of years across Asia, and every cup of true tea in the world traces back to it.
The difference is oxidation
Oxidation is the same process that turns a cut apple brown. When a tea leaf is damaged — by rolling, bruising, or simply wilting — its cell walls break and enzymes inside react with oxygen in the air. For green tea, producers immediately apply heat to deactivate those enzymes before they can do anything. For black tea, they actively encourage the process to run all the way to completion. Oolong sits anywhere in between.
Terroir still matters — just as it does in wine
Because both teas come from the same species, where the plant is grown has a profound effect on the final cup, regardless of how it is processed. A green tea from the mountains of Fujian and a green tea from Uji, Japan will taste completely different — different altitude, soil, climate, and cultivar all leave their mark. Processing style and origin together shape what ends up in your cup.
Caffeine levels are closer than you might expect
A common belief is that black tea is high in caffeine and green tea is low. In reality, the difference is modest. The caffeine content of a leaf is largely determined by the cultivar and which part of the plant was picked — young buds and first leaves are naturally higher in caffeine than older, lower leaves. Processing affects caffeine very little. Brewing time and water temperature, on the other hand, have a much larger effect on how much caffeine ends up in your cup.
There are two main varieties of Camellia sinensis: var. sinensis, a smaller-leafed plant grown across China and Japan and suited to green, white, and oolong teas; and var. assamica, a larger-leafed variety native to the Assam region of India, typically used for bold, malty black teas. Most commercial teas are hybrids of the two — but they are still, unmistakably, the same plant.