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Astringency test.

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We did about a dozen different teas a few weeks ago.

And sloshed in cream, and let the tea sit for a few hours. Then we checked just how thick the protein-tannin -rings were on the sides of the cups. (protein from the cream, tannin from the various teas: they combine, which is why you get rings in your milked-up coffee and black tea. It's as easy to uncombine them as it is to uncook boiled eggs ...)

Here's a pretty picture of the dry herbs, measured out into cups:
Pic: Astringency test herbs in cups.

First column:

  • schisandra berries, Schisandra chinensis, 20 g
  • yellowdock root, Rumex sp., 20 g
  • redroot, Ceanothus sp., 20 g
  • roseroot, Rhodiola rosea, 20 g

Second column:

  • uva-ursi leaf, Arctostaphylos uva-ursi, 5 g
  • alder cones, Alnus sp., 5 g
  • horsechestnut leaf, Aesculus hippocastanum, 5 g

Third column:

  • normal black tea, 5 g
  • ladies' mantle leaf, Alchemilla vulgaris, 5 g
  • cornflower, Centaurea cyanus, 5 g
  • red clover flowers, Trifolium pratense, 5 g

Forth column:

  • (normal coffee), 5 g
  • goldenrod flowers, Solidago virgaurea, 5 g
  • black currant leaf, Ribes nigrum, 5 g
  • calendula petals, Calendula officinalis, 5 g

Add 2 dl boiling water and let sit for 20-25 minutes. Here's a pretty picture of those infusions:
Pic: Astringency test teas, infusing.

Strain, measure out 1 dl strained tea per herb, and add 1 tablespoon cream to each cup. Let sit for 4 hours, and check how thick the rings on the sides of the cups are.

Here's a pretty pic of the strained-out teas:
Pic: Astringency test teas, strained.

The schisandra was so sour that it curdled the cream, and didn't make rings at all. That was full-fat cream ... 38 % fat.

I took pictures of the creamed-up teas, too, but they didn't amount to much, seeing that we used white cups ... it was all just an almost uniform whiteness, in the photos. Note to self: next time, use clear drinking glasses; that way, you can see the rings better, too.

And drat it, I know I wrote down which herbs were the strongest astringents in this particular test (= gave the thickest rings), but I'll have to send an email to one or the other of the students in that class, cos I just can't find my notes on it.

The strongest were, in descending order, something like: alder, rumex, uva-ursi, aesculus, rhodiola - but I'm not sure.

As a bonus you get a pic of the dried yellowdock root, all soaked up: woot, it's partly yellow! Airdried root isn't yellow at all, it's just a dark reddish-brown.
Pic: Soaked yellowdock root shows its yellow color.

(And for those using outdated measuring systems: g is gram, 1/1000 of a kg, which is kilogram. dl is deciliter, 1/10 of a liter.)

Related entry: Tannins

Update 10May06: Hah, found my notes. It's:
Strongest: alder cones
Next strongest: horsechestnut leaf and yellowdock root.
Next strongest: coffee, tea
Next strongest: ladies' mantle, cornflower and calendula.

Surprising, eh? I expect the uva ursi would give another reading if we had boiled things (= decoction), instead of just pouring boiling water over them (= infusion).


rumex above uva ursi? really?

As for "outdated measurement systems", I prefer to think of them as "traditional" or, maybe more eloquently described, "heirloom".

See, I don't remember, which is why I'm emailing one of my students.

Heirloom measurement systems? Snigger ...

well, yes, I think "heirloom" is nice... seeing our (the US's) collective dependence on the familiar standard system of measurement as the stubborn refusal to learn something new is far less appealing than seeing it as refusing to let a traditional system of measurement based on cultural identity be usurped by a number based mono-measurement system that seeks to take over the world.

How, after all, do we feel about heirloom varieties of plants being usurped by biogenitically identical plants? What if some metric-icidal pathogen were to infect scales and tape measures and beakers thrououghout the world? What would be left to save us?

Perhaps, it just might be the teaspoon.

I give you a link to one of the best Internet Oracle answers ever:
Igor Imperial vs. Mean Mr. Metric.. Enjoy!