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What roles do caffeine, tannins, and volatile oils play in tea?
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tea
Rows of tea (Camellia sinensis) growing in Japan, with Mount Fuji in the background.
In tea, caffeine, tannins, and volatile oils each serve distinct functions that define the beverage's character:
- Caffeine: This alkaloid is primarily responsible for the stimulating effect of tea on the central nervous system. While it provides this alertness, it contributes very little to the drink's color, aroma, or flavor profile.12
- Tannins: These polyphenols are the most significant chemical constituents regarding the drink's sensory profile. They are naturally colorless and bitter, providing the characteristic astringency of tea. When processed—specifically through the action of the enzyme polyphenol oxidase—they develop a reddish color and form essential flavoring compounds.13
- Volatile oils: These compounds are responsible for the distinct aroma of tea. Along with various sugars and amino acids, they play a crucial role in determining the overall quality of the beverage.1