Reducing caffeine (pre-soaking)
shrir...@gmail.com
Trying to reduce caffeine intake (I drink 4-5 cups of tea, green and
black combined) but want to preserve both flavor and flavonoids. Have
heard that since caffeine is water soluble, soaking it in 30 secs will
reduce caffeine a lot.
My question is
Does soaking it in hot water or lukewarm water make any difference in
terms of caffeine content or flavor/flavonoids.
Thanks
Shriram
Bluesea
<shrir...@gmail.com> wrote in message
news:1169881721....@a75g2000cwd.googlegroups.com...
Caffeine - yes, up to 80% in those 30 seconds. Slows down considerably after
that so there's no appreciable benefit in extending the time. I don't go
over 40-45 seconds if I can help it because too much flavor is lost with
black teas. Steep as usual except only for about 30 seconds and discard
water. Add more water to steep for drinking.
Flavor - depends. Usually varying degrees of yes for black. You'll have to
experiment because it depends on the tea. Since multiple infusions are more
typical for green teas, not really.
--
~~Bluesea~~
Spam is great in musubi but not in email.
Please take out the trash before sending a direct reply.
Nigel
do with laying. I reproduce below a posting I made on Teamail some
years ago - but I have seen no data to the contrary since:
Quote >>
After some intensive Internet trawling (nay, dredging) and poring over
a mish-mash of half truths and myth (and some of my own caffeine data
regurgitated without attribution or comprehension) I have now found
the level of data that I was advocating earlier this week - a peer
reviewed scientific paper recording precise time related extraction of
caffeine from tea using a modern detection technique (HPLC). This
paper "Tea preparation and its influence on methylxanthine
concentration" by Monique Hicks, Peggy Hsieh and Leonard Bell was
published in 1996 in Food Research International. Vol 29, Nos 3-4, pp.
325-330. (FRI is copyright of the Canadian Institute of Food Science
and Technology).
In summary Hicks et al measured the caffeine and theobromine (total
methylxanthine) content of six different teas (three bagged and three
loose leaf, including black, oolong and green types). They measured
caffeine extraction in boiling water at 5 minutes (69%), 10 minutes
(92%) and 15 minutes (100%). They replicated all their extractions
three times to eliminate error. Extrapolation of their data below 5
minutes gives the following caffeine extraction percentages (averaged
over all tea types and formats; note while loose tea extracted
marginally more slowly than teabag tea it made only a couple of %
points difference):
30 seconds 9%
1 minute 18%
2 minutes 34%
3 minutes 48%
4 minutes 60%
5 minutes 69%
10 minutes 92%
15 minutes 100%
This is very much at odds with the mythical "30 or 45 second hot wash
to remove 80% of the caffeine" advice - as a 30 second initial wash of
the tea will actually leave in place 91% of the original caffeine!
I commend the paper to anyone seeking further data.
>>Unquote
If anyone has better evidence (based on actual analysis) about the
efficacy or otherwise of hot water decaffeination I would very much
like to hear it.
Nigel at Teacraft
On Jan 27, 5:09 pm, "Bluesea" <thisa...@is.invalid> wrote:
> <shriram...@gmail.com> wrote in messagenews:1169881721....@a75g2000cwd.googlegroups.com...
>
> > Hi
>
> > Trying to reduce caffeine intake (I drink 4-5 cups of tea, green and
> > black combined) but want to preserve both flavor and flavonoids. Have
> > heard that since caffeine is water soluble, soaking it in 30 secs will
> > reduce caffeine a lot.
>
> > My question is
>
> > Does soaking it in hot water or lukewarm water make any difference in
> > terms of caffeine content or flavor/flavonoids.Caffeine - yes, up to 80% in those 30 seconds. Slows down considerably after
Lewis Perin
> [...the idea that caffeine can be easily soaked away...]
>
> This is wishful thinking and an oft repeated tea myth that could well
> do with laying. I reproduce below a posting I made on Teamail some
> years ago - but I have seen no data to the contrary since:
> [...]
>
> In summary Hicks et al measured the caffeine and theobromine (total
> methylxanthine) content of six different teas (three bagged and three
> loose leaf, including black, oolong and green types). They measured
> caffeine extraction in boiling water at 5 minutes (69%), 10 minutes
> (92%) and 15 minutes (100%).
Thanks, Nigel, for taking the trouble to swat down this endlessly
recurring rumor!
This may seem like a small point, but I wonder if "boiling water" here
means water that was boiled or water that continues to boil for the
duration. At 15 minutes that could make a big difference.
/Lew
---
Lew Perin / pe...@acm.org
http://www.panix.com/~perin/babelcarp.html
toci
need the caffeine the most. Then a second steep from the same leaves
or a cup of low caffeine black next. Then switch to green, using the
same leaves for any further steeping for the rest of the day.
Toci
HobbesOxon
some interesting conclusion. In the following, I use "black tea" in
its Western sense, as in the paper (these being the usual Kenyan/
Ceylon/Assam varieties used in Lipton blends).
- Wulong (Taiwanese) was found to contain more caffeine in typical
brews than loose-leaf black tea. This was because the brewing
parameters for each type of tea were taken from the tea packaging, and
the wulong packaging suggested using more leaf. Personal experience
supports this - I tend to use more wulong leaf than darjeeling/assam/
hongcha/pu'er (though you, of course, may not!).
- Caffeine-per-gram was highest in loose-leaf black and green teas
(identical at 36.6 mg caffeine per g of leaf), with less in loose-leaf
wulong (28.8 mg / g). This is supported by the oft-touted
conventional wisdom that black teas contain high caffeine quantities -
though I was surprised to see that the loose-leaf green (a "Korean")
was similar.
- Bagged teas were seen to contain less caffeine than loose-leaf tea
in the initial (5 min) infusion, rapidly tailing off to caffeine
levels of bagged tea being *much* less than loose-leaf tea in
subsequent infusions. However, the authors noted that the bagged tea
only retained their flavour for the first infusion (heh).
- Wulong lost its caffeine the fastest of all the loose-leaf teas, but
all teas had >65% caffeine left in the leaves after the 1st infusion.
Note that the brewing method was placing the tea into boiling water
and infusing for 5 mins without keeping the water boiling! This was
intended to simulate slower "Western" brewing.
Previous studies recommened drinking "10 cups of tea per day" in order
to protect against cancer. This was recently echoed by the BBC in an
article that I linked here. However, this is (as the authors state)
quite misleading: if one takes 10 cups of tea brewed "Western" style,
using teabags, and not re-using them, the caffeine intake is pretty
huge. It's way over the 300 mg / day limit that induces "headaches,
nervousness, irritation" and other health problems. Drinking 10 cups
of reinfused loose-leaf tea did not result in such high caffeine
intake (~ <= 300 mg/day), indicating that one could achieve the
potential health benefits from the polyphenols without causing damage
due to drinking too much caffeine.
For some reason I am reminded of MarshalN's blog. Heh. :)
Thanks again for the reference, and toodlepip,
Hobbes
P.s. Readers interested in a PDF version of the paper may wish to
contact me.
P.p.s. On re-reading, I notice that the < 5min caffeine levels were
interpolated by you (presumably, linearly). It might be best to warn
readers that these figures are only estimates - as far as we know,
much more caffeine might be released in the first 30s than the last
4.5 mins! Of course, it's fine as far as outline guides go, but I
would be wary of stating as fact that "only 9% of caffeine is removed
in the first 30s" just to be on the safe side. :)
P.p.p.s. The time between 5 min infusions was considerable ("the brew
was allowed to cool to room temperature"), giving the leaves a
particularly long rest.
Space Cowboy
is adding boiling water for three minutes in 1/2L pot for any tea.
The first pot is the euphoric hum with an occasional oolong and green
which might make a second pot tasting flat but no buzz. I think
smaller pots saturate faster limiting extraction while I go for the
gusto in the first pot. I know I don't leave 50 percent of the
caffeine in the pot. Don't sip tea. Coat your throat and warm your
stomach.
Jim
On Jan 30, 8:56 am, "Nigel" <n...@teacraft.com> wrote:
> This is wishful thinking and an oft repeated tea myth that could well
> do with laying. I reproduce below a posting I made on Teamail some
> years ago - but I have seen no data to the contrary since:
...I don't gamble in Lost Wages....
Lewis Perin
> Fascinating, thank you for the reference, Nigel. The paper itself has
> some interesting conclusion. In the following, I use "black tea" in
> its Western sense, as in the paper (these being the usual Kenyan/
> Ceylon/Assam varieties used in Lipton blends).
> [...]
> - Caffeine-per-gram was highest in loose-leaf black and green teas
> (identical at 36.6 mg caffeine per g of leaf), with less in loose-leaf
> wulong (28.8 mg / g). This is supported by the oft-touted
> conventional wisdom that black teas contain high caffeine quantities -
> though I was surprised to see that the loose-leaf green (a "Korean")
> was similar.
I think it's safe to say that this is because oolong is typically made
from big, mature leaves. Caffeine content is higher the closer a leaf
is to the growing tip. Decent greens and blacks are made with leaves
close to the bud.
HobbesOxon
You wrote:
> I think it's safe to say that this is because oolong is typically made
> from big, mature leaves. Caffeine content is higher the closer a leaf
> is to the growing tip. Decent greens and blacks are made with leaves
> close to the bud.
I can't comment on the second sentence, because I'm not sure how the
caffeine content in leaves varies from tip to "xiaozhong", but I don't
know how safe it is to say that wulong is made from big, mature leaves
- there's a significant amount of "tippy" wulong for sale from the
Usual Suspects that I rather enjoy.
I definitely agree that good greens and blacks are tippy - as long
as we restrict our definition of "black" to the western definition.
There are some great Mainland hongcha varieties that are large in
size, and clearly pu'er can be very large (depending on which "colour"
one assigns to pu'er!).
Most surveys quoted on this forum, and on other sites around
t'Interweb lists green teas as being the "low caffeine" alternative.
I was somewhat surprised to see the results shown in this paper, in
which the "Korean" was almost exactly the same in caffeine
concentration as the black leaves. Perhaps all that is needed is a
larger sample size in this case. What say you? It certainly seems to
fly in the face of received wisdom (and in the advertising of many tea
merchants). :)
Addio addio,
Hobbes
Lewis Perin
> Dear Lew,
>
> You wrote:
>
> > I think it's safe to say that this is because oolong is typically made
> > from big, mature leaves. Caffeine content is higher the closer a leaf
> > is to the growing tip. Decent greens and blacks are made with leaves
> > close to the bud.
>
> I can't comment on the second sentence, because I'm not sure how the
> caffeine content in leaves varies from tip to "xiaozhong", but I don't
> know how safe it is to say that wulong is made from big, mature leaves
> - there's a significant amount of "tippy" wulong for sale from the
> Usual Suspects that I rather enjoy.
I'm sorry if I left the impression that there'd be no exceptions.
> I definitely agree that good greens and blacks are tippy - as long
> as we restrict our definition of "black" to the western definition.
> There are some great Mainland hongcha varieties that are large in
> size, and clearly pu'er can be very large (depending on which "colour"
> one assigns to pu'er!).
Yes, but when you're talking about the Yunnan Da Ye cultivar, Tippy
doesn't necessarily Small.
> Most surveys quoted on this forum, and on other sites around
> t'Interweb lists green teas as being the "low caffeine" alternative.
> I was somewhat surprised to see the results shown in this paper, in
> which the "Korean" was almost exactly the same in caffeine
> concentration as the black leaves. Perhaps all that is needed is a
> larger sample size in this case. What say you? It certainly seems to
> fly in the face of received wisdom (and in the advertising of many tea
> merchants). :)
See, for example,
http://www.holymtn.com/tea/teacaffeine.htm
Nigel
"received wisdom" on caffeine. Their data indicates it to be (on
average) neither higher nor lower in white, green, black or pu'erh.
Caffeine differences are principally due to genome (China type - tend
lower, or Assamica type - tend higher) or to nutrition (N makes
caffeine higher), to season (fast growth makes caffeine higher) and to
manufacture (can manipulate it up or down) - all these inlences can
act together or against each other .
If I may again quote from another posting I made on Teamail (30th July
2004) in reply to some muddled thinking.
Teamail Quote>>>>>>>>>>>>>>>
The subject of caffeine in various types of tea has come up again.
Last time it surfaced I couldn't locate the data, but now here is what
I have.
Experimental process runs (were) undertaken in the Teacraft ECM System
for precision miniature tea manufacture "the tea factory in a box".
This system allows any environmental variable to be controlled to a
set value while the other variables are held rock solid - and gained
the American Society of Agricultural Engineers' AE50 Award for
"outstanding technological innovation". Too expensive for home use, I
fear.
1. Effect of wither conditions on caffeine level - same leaf into all
experimental conditions, all leaf 2L&B standard, one named clone.
Fast wither (8 hours to 70% moisture content)
Wither at 15 deg C caffeine 3.20%
Wither at 25 deg C caffeine 3.45%
Wither at 35 deg C caffeine 3.30 %
Slow wither (18 hours to 70% moisture content)
Wither at 15 deg C caffeine 3.10%
Wither at 25 deg C caffeine 3.65%
Wither at 35 deg C caffeine 3.43 %
A quadratic response in each set.
2. Effect of length of wither on caffeine level (hours to 70% moisture
content) each
run replicated - 2L&B hybrid seedling leaf used.
10hr 3.20, 3.23% = 3.22%
14 3.38, 3.41% = 3.40
18 3.38, 3.47% = 3.43
22 3.50, 3.52% = 3.51
30hr 3.53, 3.58% = 3.56%
Straight line response, no effect of wither moisture level, best
response at 25 deg C
3. Effect of fermentation duration (minutes) on caffeine level
(average of four clones)
0 3.20%
30 3.02
45 2.98
60 2.88
75 2.80
90 2.72%
Straight line response
4. And a little hard data from another source:
Seasonal variation in % caffeine level - Kenya
Dec Apr Jul Sep
Clone 1 2.9 2.4 1.4 2.4
Clone 2 3.1 2.3 1.5 2.6
Clone 3 3.2 3.1 1.8 2.7
Clone 4 4.0 3.9 1.9 2.9
Absolute min/max Caffeine range through year
Clone 1: 1.2 & 3.2%
Clone 2: 1.3, & 3.4%
Clone 3: 1.7 & 3.9%
Clone 4: 1.9 & 5.0%
Qusetion - Is Clone 4 a high or low caffeine type?
I have shown here a few of the factors that can change and determine
caffeine level in a made tea. Other important factors are level of
nutrition (goes up with nitrogen) and degree of leaf shading.
All of which goes to show that quoting any particular caffeine
percentage for a given tea type (and many people do) should be fringed
with caveats and exact data given as to how it was processed and when
it was grown. In the main none of this information is available to
the producer, let alone the seller.
>>>>>>>>>>>>>Unquote
Which all goes to show that caffeine levels quoted either in sweeping
generalizations or as absolute truth should be laughed at - at best
(using HPLC analysis) a precise and accurate caffeine content is but a
snapshot in time.
Nigel at Teacraft
On Jan 31, 5:43 pm, Lewis Perin <p...@panix.com> wrote:
> > Most surveys quoted on this forum, and on other sites around
> > t'Interweb lists green teas as being the "low caffeine" alternative.
> > I was somewhat surprised to see the results shown in this paper, in
> > which the "Korean" was almost exactly the same in caffeine
> > concentration as the black leaves. Perhaps all that is needed is a
> > larger sample size in this case. What say you? It certainly seems to
> > fly in the face of received wisdom (and in the advertising of many tea
> > merchants). :)
>
> See, for example,
>
> http://www.holymtn.com/tea/teacaffeine.htm
>
> /Lew
> ---
> Lew Perin / p...@acm.orghttp://www.panix.com/~perin/babelcarp.html
Bluesea
I first learned of the 30 sec. decaf process back in '98-'99 and was given
the source reference. As it was so long ago, I can't remember it. As I'm not
at home, being on a long road trip, I'm not able to provide it.
Perhaps the OP or any other interested parties may want to contact the
various tea vendors who advocate this DIY method. Upton's, for example,
usually cites references for their articles and may be willing to provide
their source for this info, too.
--
~~Bluesea~~
Spam is great in musubi but not in email.
Please take out the trash before sending a direct reply.
"Nigel" <ni...@teacraft.com> wrote in message
news:1170172613.2...@a34g2000cwb.googlegroups.com...
DogMa
to me both as an example of the gratuitous pseudo-scientific mysticism
that displaces so much that is truly useful in tea lore and tea
thinking, and of the way that advertisers casually sling BS that doesn't
help and often harms tea-drinkers.
Nigel wrote:
> This is wishful thinking and an oft repeated tea myth that could well
> do with laying.
Thanks for your post, Nigel.
> ... a peer reviewed scientific paper recording precise time related
> extraction of caffeine from tea using a modern detection technique
> (HPLC).
The only way to fly. Too bad they didn't take a few more low-time data
points, but it's enough to make the lesson clear, as you indicate.
> ... 5 minutes (69%), 10 minutes (92%) and 15 minutes (100%).
When plotted with the origin, these make a pretty typical-looking
extraction curve. I would draw an even stronger conclusion than Nigel
from the low-time interpolated data. Since the authors used powdered
tea, extraction kinetics only model part of what happens in normal use.
In particular, for the first several seconds of steeping, leaves are
imbibing water rapidly, and very little material is leaving the leaf. So
a real-life extraction curve is sigmoidal (S-shaped), with almost
nothing happening for a period of time that might approach 15 seconds
for some unbroken leaves.
> This is very much at odds with the mythical "30 or 45 second hot wash
> to remove 80% of the caffeine" advice - as a 30 second initial wash
> of the tea will actually leave in place 91% of the original caffeine!
I'm just a chemist; Nigel's the tea-science guru here and I defer to
him. I suspect that we agree, though, that rinsing to remove caffeine
will only work at all on CTC-type fragments where much of that component
is in fast-dissolving dried juices outside the cellular structure. In
this case, desirable flavor and alleged healthful effects will depart as
fast as caffeine. With whole-leaf teas, the notion that caffeine can be
removed selectively makes little theoretical sense, and the present
result supports that.
Many years ago, I had the un-original idea of using ice-water to
extract caffeine while leaving everything else intact. It doesn't work,
since many important flavor components are about as soluble in cold
water as is caffeine. Amino acids and sugars are examples. What doesn't
come out so fast is astringent tannins, which is why some of us prefer
cooler brewing styles. I think it fair to say that there is at present
no practical way for the average home user to decaffeinate high-quality
tea. It certainly could be done, by all sorts of affinity sorption
techniques, perhaps embodied on a stick or straw. But I doubt that
anyone will spend the development money to achieve this unless a lot of
tea-drinkers present a collective marketing case to the biochemical and
foods companies that command this technology.
-DM
Space Cowboy
styles of making tea. Just more meaningless factoid science.
Jim