I have noticed that when brewing a variety of teas that the first 1-2
brews will sometimes generate a foam. I have been taught that if this
happens when brewing in a gaiwan to just scrape the foam off with the
lid and discard.
My question is, what causes the foam? Is it debris/dust in the leaf?
Is it chemical residue? Is it a plant constituent?
I have noticed this foam on both oolongs and sheng puerhs (the teas
that I primarily drink), and in the case of puerhs, I notice it very
often on Xia Guan produced teas.
Any info or advice?

Thanks
David L.

Look at similar posts in the past with Google. I don't think it is a
chemical residue because drinking that much you would be dead in a
short time. My theory was dry leaf condition where the hot water would
scour the leaf for much smaller particulate. Whatever it is, it is
lighter than water to cause the foam. It is a common desired condition
in British Indian blends. Then I got large quantities of Yunnan Black
Gold and Fujian BaiMuDan. You can see the particulate in the leaf.
The particulate clings to the lining of the container. I've concluded
it is hair from the bud. It produces the same foaming action I see
with some Indian blends. You can guage Indian blends by course or fine
pluckings. In other words, the more bud the more foam from the
macerated hair you can't see. I can get some foaming action with
almost any oolong or black tea just from the type of pot and furious
rolling pour but the foam quickly disappears. Here I am talking about
the mad dog variety. I drink shu off the top and I've never noticed
any foaming, fizzing yes. I wouldn't expect any just by the way I brew
it.

Jim

Davelcorp wrote:
I have noticed that when brewing a variety of teas that the first 1-2
brews will sometimes generate a foam. I have been taught that if this
happens when brewing in a gaiwan to just scrape the foam off with the
lid and discard.
My question is, what causes the foam? Is it debris/dust in the leaf?
Is it chemical residue? Is it a plant constituent?
I have noticed this foam on both oolongs and sheng puerhs (the teas
that I primarily drink), and in the case of puerhs, I notice it very
often on Xia Guan produced teas.
Any info or advice?

Thanks
David L.

Sometimes proteins released from the leaves can add to the phenomenon.

Karsten [N 53°13' - E 7°46']