The main categories of tea are green, black, and oolong. White tea is now becoming more popular and readily available. All are made from the same Camellia sinensis plant species. The processing methods that tea undergoes determines which category it will fit into. Black teas undergo several hours of oxidation in their preparation for market; oolongs receive less oxidation, and green teas are not oxidized at all.
Across the globe, more than 3000 different teas are made from different varieties of the Camella sinensis. Like wine, variation in flavour occurs due to the altitude, soil, and other environmental conditions. The variability in processing also leads to the many tea varieties.