I'm a tea lover, too. I just read an interesting article about a genetically-deficient species of tea called HongYaCha. HYC cannot make caffeine because it has a mutation in caffeine synthase, according to https://steemit.com/steemstem/@diamondmind/a-compilation-of-information-on-alternative-medicine-how-anticancer-drugs-can-be-produced-in-yeast-a-new-tea-plant-with-low