why tea stains my cup but not coffee?

Question

I’m a lifelong coffee drinker but I recently changed to tea. I noticed that all my cups are suddenly covered in brown stains on the inside. It seems weird because coffee is much darker.
Why does tea stain more?

In: Chemistry

Answer 1

Tea contains tannins, or tannic acid, that leaves stains. Coffee doesn’t have tannins. Red wine would stain a ceramic mug for the same reason.