Question

If you used different branded of tea beg what is the expected % of coffeine you will isolated. Why?

Answer 1

You need to look on the boxes or on the internet and find % caffeine in each bag and/or each serving of tea. I think you may come up largely empty handed because the FDA does not require that to be listed. I went through the same kind of thing for decaffeinated coffee and found some but not all of what I wanted.