This! Another curious thing I have noted: While living in Japan I was binging on houjicha[0] (which has significantly less caffeine due to the roasting process

This! Another curious thing I have noted: While living in Japan I was binging on houjicha[0] (which has significantly less caffeine due to the roasting process) on late evenings so I would still be able to sleep. After several strong pots (we are talking litres of 1:1 water/leaf ration) I would often get into a different mind-space that is pretty close to what you are talking about. I tried to research if other catechins (like l-theanine) also disappear in the roasting process or if they could be the explanation, but weren't able to find anything to back this up. 0: https://en.wikipedia.org/wiki/H%C5%8Djicha https://en.wikipedia.org/wiki/H%C5%8Djicha