Re: why does adding lemon to tea lighten it's color?

Hi Amy

Tea contains natural acid/base indicators, namely tannins. At high pH (basic), the tannins have a dark brown color, while at lower pH (acidic), they become a golden-yellow-to-orange color. Adding the lemon juice drops the pH, and thus might appear to lighten the solution.

If you want to experiment further, try adding some sodium bicarbonate (baking soda, a base) to your lightened solution. It should turn back to it's dark brown color. Likewise, try adding other acids, such as vinegar (acetic acid solution).

Cheers..

-L. Bry, MadSci Admin