Caffeine in roasted vs. unroasted oolong?

[teashionista]

I know the topic of caffeine in different types of teas has been discussed several times here. But I couldn't find the answer to this: does roasting reduce levels of caffeine in oolong?
Since houjicha has significantly less caffeine than bancha (which is removed, I assume, by roasting), would the same theory apply to oolongs? I.e. would a heavily roasted TGY have less caffeine than its unadulterated sibling?

[Chip]

That is an interesting question ...

I had read that it is more when green bancha is slowly roasted into bancha that its caffeine is reduced ... which I would then extrapulate that fast roasting would not.

So, perhaps the way it is roasted would also have some effect in oolong?

[OchameTaiken]

Yes, indeed roasting is one of the factors that has a concrete effect on caffeine content.

Just as with the houjicha, oolong tea that is roasted or baked will also see a reduction in caffeine. When tea is roasted it gives off a bitter, white powder (guess what it is!) Mr. Kaiser from Rishi shared this photo of him in a tie guan yin roasting room.

When aged oolong is repeatedly baked periodically, it leaves behind more caffeine with each baking. So, if you assume all else equal between two like teas, the more roasted can be safely assumed to have less caffeine.

[Chip]

Interesting, so this white powder just drops off the leaf during roasting? Somehow I just thought or assumed the caffeine was simply altered in roasting.

But, I honestly have no clue ...

[teashionista]

Thanks for the info, OchameTaiken!

[OchameTaiken]

Interesting, so this white powder just drops off the leaf during roasting? Somehow I just thought or assumed the caffeine was simply altered in roasting.

Certainly some caffeine is actually liberated from the leaf. Granted the circumstances here are on a much larger scale, but you could try roasting your own green tea into houjicha at home, and see if you notice a little bit.

[Chip]

Actually I do make my own Houjicha ...

I guess my point is, if the white powder is still on the leaf, the caffeine is still present in the brew?

It seems to me that something happens to the caffeine as in it is neutalized in the roasting. Either that or Houjicha and roasted oolong are not really that low in caffeine?

[OchameTaiken]

Not affixed to the leaf. The caffeine is found left behind in the baking drum/oven. (Or dispersed in the air, as the case may be seen above!)

[DJ3riple]

Cool, thanks for the info OchameTaiken

[Dresden]

Now that you mention it, I did notice a small amount of white powder in the pan after home-firing some houjicha.

Interesting!