Foam ?


One of the intentionally aged teas, Pu-Erh has a loyal following.

Re: Foam ?

Postby tenuki » May 31st, '13, 17:51

All of you need to stop making stuff up and read the science on

TEA SCUM
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Re: Foam ?

Postby gingkoseto » May 31st, '13, 19:38

Evan Draper wrote:
gingkoseto wrote:Pectin contents

Gingko, can you cite some stuff about pectin in tea? Never heard it mentioned before. I can see that pectin would increase viscosity, but I don't see how it would produce bubbles. Perhaps pectin is the glycoside moiety of tea saponin, and perhaps I'm talking through my hat.


In Chinese, pectin is translated as "fruity gel", because pectins are the poly-sugars commonly found in fruits that's responsible for some good flavors and smooth-sticky mouth-feels. Pectin can increase the surface tension of a liquid and therefore causes bubbles.

Most of my conversations about pectin are with the oolong people, as pectin is a big thing in oolong connoisseurship. It's responsible for part of the fruity flavors in oolong and the smooth liquor texture.

But talking about puerh, here is a relatively new paper about pectin in shu (English abstract from original article):

(The PI/last author of this article is the author of my favorite tea book
http://www.teachat.com/viewtopic.php?f=11&t=5055&start=15)

2012, 39(4): 580-584
Journal of Anhui Agricultural University
http://www.cnki.net/kcms/detail/34.1162.S.20120704.1722.001.html (not a useful url as it requires login)

Changes of tea polysaccharide and pectin during fermentation process of Pu-erh tea
ZHAO Xue-feng, PENG Chuan-yi, GU Xun-gang, WAN Xiao-chun
(Key Lab of Tea Biochemistry & Biotechnology, Ministry of Agriculture, Anhui Agricultural University, Hefei 230036)
Abstract:The conventional methods were employed to investigate the change rules of tea polysaccharides
and pectin contents in the pile-fermentation of Pu-erh tea samples collected from production workshop. The
results indicated that the total contents of tea polysaccharide and water-soluble pectin were gradually increased
with prolonging of the pile-fermentation time in the sample, however, the water-soluble pectin in the fourth
pile-fermentation sample trended to decrease until to the end of pile-fermentation process, which almost kept at
the same level. Both of tea polysaccharide and water-soluble pectin contents at end-fermentation sample were
closed to the maximum value, which were probably the important components to form the special taste of
Pu-erh tea, and had a potential health protection function. The change of the protopectin was not regular, which
trended to decrease in the beginning of pile-fermentation process, and to increase at the end of fermentation
step, which was suggested to be correlated with polymerization of water-soluble pectin. We also investigated
the contents of the polysaccharide and pectin in several typical tea species. Generally,the contents of tea poly-saccharide and water-soluble pectin inthe fermentative tea samples were much high, which maybe due to mi-crobe’ degradation in transforming some matrices into water-soluble components. The contents in
non-fermentative and semi-fermentative tea samples were very low, which did not affect the quality of the cor-responding tea because of different special taste.
Key words:Pu-erh tea; pile-fermentation; tea polysaccharide; pectin
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Re: Foam ?

Postby Drax » May 31st, '13, 20:37

Huh, interesting.

Is it this quality that allows the creation of those reductions? (the shu pu tea gels)
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Re: Foam ?

Postby Evan Draper » Jun 1st, '13, 12:50

tenuki wrote:TEA SCUM

Funny! I read one of those papers, and I think they're different phenomena. The researcher is using London tap water and one Typhoo teabag. The scum he's talking about is a surface film which is primarily composed of calcium carbonate from the water. Incidentally, he recommends lemon juice as a fix....
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Re: Foam ?

Postby wyardley » Jun 1st, '13, 14:14

Maybe this thread could be moved to "other tea", since it's not pu'er specific? In fact, I see a lot more foam with roasted oolongs than with most pu'ers.
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