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Why is Tea Red?

Published in Tea Chemistry 2 mins read

Red tea is red primarily because it undergoes a full oxidation process during its production.

Here's a more detailed explanation:

  • Oxidation: Tea color and flavor are determined primarily by oxidation. This process involves exposing the tea leaves to air, which triggers enzymes to react with the leaf's compounds.

  • Level of Oxidation: Different types of tea are oxidized to varying degrees:

    • Green Tea: Undergoes minimal to no oxidation.
    • Black Tea (often called "red tea" in some Asian cultures): Is fully oxidized, resulting in its distinctive dark color and robust flavor.
  • Chemical Changes: The oxidation process transforms the chemical compounds in the tea leaves, including:

    • Polyphenols: These antioxidants react with oxygen, creating larger, darker molecules. This darkens both the leaves and the brewed tea.
    • Tannins: Oxidation affects the tannins, which contributes to the tea's astringency and color.
  • Terminology: It's important to note that "red tea" can be confusing:

    • In Western cultures, "red tea" commonly refers to Rooibos tea, which is naturally red due to its own unique set of chemical compounds. Rooibos is not derived from the Camellia sinensis plant (the plant from which green and black teas originate) and it is technically not a true tea.
    • In China, "red tea" (红茶, hóng chá) actually refers to what Western cultures call black tea.

Therefore, to clarify: Black tea (sometimes referred to as red tea, especially in Chinese terminology) is red due to the full oxidation of its leaves, while Rooibos tea (also called red tea) is red due to the natural characteristics of the plant it comes from.