Why is my green tea foaming too? I buy organic, loose green tea from a co-op and found that it's sourced from China.  I've never had tea foam before and am concerned that the tea has some kind of chemical on it.  The foam tastes very bitter.  It made me throw the tea out.  I know that the FDA only checks randomly at the port so I'm leary of what's making it foam.  Many years of tea making and this is a first.
Does anyone have any experience or answers for this?
Thank you!
The pouring of water over the tea adds oxygen, which stirs up tannic acid in the tea and causes it to foam. Stirring vigorously also adds air, leading to foam from the tannic acid.