tag:blogger.com,1999:blog-8825055425170299721.post5161430076699544456..comments2024-03-20T16:34:04.414-04:00Comments on Alex Zorach's Tea Blog: Scientific Research I'd Like To See Done on Tea's Caffeine, Vitamin C, etc.Alex Zorachhttp://www.blogger.com/profile/08335878680429494039noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-8825055425170299721.post-31962978807423379802012-04-25T16:32:42.969-04:002012-04-25T16:32:42.969-04:00Thanks...I began integrating some of this new info...Thanks...I began integrating some of this new info into the article on RateTea on the <a href="http://ratetea.com/topic/caffeine-content-of-tea/21/" rel="nofollow">caffeine content of tea</a>, it's just a beginning...there is still a lot of material I can add to the other articles on the site, and probably more I can add to the caffeine article too.Alex Zorachhttps://www.blogger.com/profile/08335878680429494039noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-80903152180766178052012-04-25T16:31:48.797-04:002012-04-25T16:31:48.797-04:00Thanks, I've updated the article on the caffei...Thanks, I've updated the article on the <a href="http://ratetea.com/topic/caffeine-content-of-tea/21/" rel="nofollow">caffeine content of tea</a>, and linked to this analysis by the Camellia sinensis tea house, which I found interesting and informative!Alex Zorachhttps://www.blogger.com/profile/08335878680429494039noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-56273202538692227902012-04-11T23:04:32.253-04:002012-04-11T23:04:32.253-04:00Hi Scott, I have very limited experience in Indian...Hi Scott, I have very limited experience in Indian and Ceylon teas. But I think your question about re-steepability is a good one! Even when we compare different types of Chinese black teas, they yield very different numbers of infusions. I would like to spend some time thinking about it!Gingkohttps://www.blogger.com/profile/00717840609096741544noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-2688074612671861202012-04-11T03:42:14.608-04:002012-04-11T03:42:14.608-04:00I think most of the papers listed do test for stat...I think most of the papers listed do test for statistical significance and report on it. The issue may be more of a "type of study" -thing, owing to the fact that the chemical composition of tea is a result of a very complex interaction of factors. <br /><br />For example, from the research I've read it seems that cultivar is the single most influential factor in determining caffeine and polyphenol contents of teas. These results seem solid, because across the studies, there are hundreds of samples and repeated tests, and because it has been possible to eliminate the many confounding factors to a great extend: the teas tested generally come from tea germplasm repositories, where the different cultivars have been nurtured and processed in the same way, in the same soil and climate conditions. <br /><br />Then, recognizing this, one of the studies on using polyphenols as geographical indicators in Japan was able to rule out the effect of cultivar by making sure each of their samples was of the Yabukita stock.<br /><br />Similarly, at least the best study on weather and soil effects in different locations made sure to use same cultivar teas from the same producer with the same care instructions, to try to filter out any potential effects different management would have on the results.<br /><br />Now, on the other hand, the studies comparing commercially available teas generally can neither restrict nor expand their sample to cover all combinations, so with them one is stuck with averages. But they're still useful, just answering different questions. For example, based on the research I've read it seems that on <i>average</i>, black teas available in Middle Europe: 1) have more caffeine and EGCG than green teas, 2) Their instructions on average specify usage of more leaves, longer infusion times and more water, 3) The leaves of black teas are more often CTC manufactured and 4) The green teas are more often artificially flavored (=generally of poorer original quality). <br /><br />While this doesn't tell us anything about green vs. black or CTC vs orthodox in general, combined with the more isolated factor studies it can give us additional information on the experience of the general population on a more general level with regard to for example experiencing the amount of caffeine in green vs. black tea.Anonymoushttps://www.blogger.com/profile/09775569473253000646noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-53855364233585231612012-04-10T16:40:29.428-04:002012-04-10T16:40:29.428-04:00Thanks, I really don't know what's out the...Thanks, I really don't know what's out there in non-English-language sources, and it seems plausible that there's be a lot of research in China, Taiwan, and Japan that is not translated to English.<br /><br />Thanks for these links too.<br /><br />I haven't looked through these individual studies, but when doing my research, there were a lot of studies that I found it was hard to draw conclusions from, because they would draw conclusions using averages, but when you examined their data, the samples were too variable from one specific tea to the next to actually say anything about ranking them. Glancing over the abstract of some of these, esp. the effects of various factors on the chemical composition of teas, I'm wondering if these studies are similar. In order to really say that one category is > or < another category in any respect, one needs to have a representative sample of what's out there, and a large enough sample size that you can get statistical significance. That's been missing in every study I have looked at so far.Alex Zorachhttps://www.blogger.com/profile/08335878680429494039noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-47615390870295933792012-04-10T16:28:46.521-04:002012-04-10T16:28:46.521-04:00I disagree on the amount of tea research out there...I disagree on the amount of tea research out there. <br /><br />From what I've seen, there are two major sources constantly pushing out tea research: 1) major international tea companies (e.g. Lipton) and 2) tea research institutes in the various tea growing regions (Taiwan, China, Japan, India).<br /><br />The scientists in the former of these publish mostly on the health benefits of tea, but those in the latter publish on a wide range of topics, such as the factors affecting and effects of cultivation, cultivars, processing methods, chemical composition, quality metrics, the particular species of fungi involved in puer production and so on.<br /><br />The problem until recently with all the research in this latter group was that most of it was being done in China, Taiwan and Japan. They then published in Chinese and Japanese in their own forums, and not in international science journals in the English we can read. However, I think I've seen a shift happening here particularly since the early 2000's, with more and more research from the east also starting to appear in English language journals.<br /><br />For example, here are some article lists pertaining to the themes you've highlighted, coming from research I did into a scientific article I'm currently drafting on the "Factors Affecting the Actual and Perceived Amount of Caffeine in Tea" (interim presentation available <a href="http://www.uutos.fi/wp-content/uploads/2012/03/teacaffeine.pdf" rel="nofollow">here</a>):<br /><br />* <a href="http://www.mendeley.com/groups/2083513/uutos-research/papers/added/0/tag/quality/" rel="nofollow">On the relations between the chemical composition and the (perceived) quality of tea</a><br />* <a href="http://www.mendeley.com/groups/2083513/uutos-research/papers/added/0/tag/commercial+comparisons/" rel="nofollow">Comparisons of chemical composition between different commercially available teas of various types and qualities in different regions around the world</a><br />* <a href="http://www.mendeley.com/groups/2083513/uutos-research/papers/added/0/tag/processing/" rel="nofollow">On the effects of processing methods on the chemical composition of tea</a><br />* <a href="http://www.mendeley.com/groups/2083513/uutos-research/papers/added/0/tag/origin%3A+cultivars/" rel="nofollow">On the effects of cultivar on the chemical composition of teas</a><br />* <a href="http://www.mendeley.com/groups/2083513/uutos-research/papers/added/0/tag/origin%3A+geography/" rel="nofollow">On the effects of geography on the chemical composition of teas</a><br />* <a href="http://www.mendeley.com/groups/2083513/uutos-research/papers/added/0/tag/origin%3A+seasons/" rel="nofollow">On the effects of seasons on the chemical composition of teas</a><br />* <a href="http://www.mendeley.com/groups/2083513/uutos-research/papers/added/0/tag/infusion/" rel="nofollow">On the how various infusion parameters affect the composition of the final drink</a>Anonymoushttps://www.blogger.com/profile/09775569473253000646noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-25707814715101854372012-04-09T15:07:27.392-04:002012-04-09T15:07:27.392-04:00I was able to brew the Putharjhora for many (5+ in...I was able to brew the Putharjhora for many (5+ infusions) by using more leaf, as I would a Pu-erh. I did not mention this in my review because I found I did not enjoy the tea as much this way. When using more leaf and briefer (~1 minute) infusions, the tea changed quite a lot in character from one infusion to the next. I liked brewing the tea in two long infusions because this created more complexity, there was a confluence of the different characteristics of aroma.<br /><br />It's a matter of personal taste, largely, I think.<br /><br />One Indian company, which has since closed, <a href="http://ratetea.com/brand/fresh-darjeeling-tea/86/" rel="nofollow">Fresh Darjeeling Tea</a>, gave brewing instructions for multiple steepings. They sold a lot of white, green, and oolong Darjeelings though...I actually only tried one black tea from them, and it was fairly atypical too.Alex Zorachhttps://www.blogger.com/profile/08335878680429494039noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-1691364327227743702012-04-09T11:42:19.154-04:002012-04-09T11:42:19.154-04:00Hmm, I will have to keep experimenting and see if ...Hmm, I will have to keep experimenting and see if perhaps I jumped to a conclusion too soon. But I do note that I've come across several sellers of Chinese tea who claim 3 to 5 good Western-style infusions for their black teas, like Seven Cups and Verdant Tea (check the brew instructions on these sellers' websites). I don't see anyone selling Indian tea making these claims. Also, the only black teas I've had so far that took well to 3+ infusions were Chinese, "Yunnan Gold" and "Golden Monkey" style specifically.<br /><br />I feel the closest I've gotten with Indian black teas was also a Makaibari, in my case their excellent second flush sold by Silver Tips. I found that by shortening the first steep I could get two steeps out of it; but even so, both were somewhat weak in flavor as a result.<br /><br />In contrast, the Yunnan Royal Gold I just ran out of :( from Northern Lights Tea would give three great steeps at 212°F, 2:30, 3:30, 4:30, the last as good as the first.<br /><br />Do you know an Indian or Ceylon black tea that gives a strong third infusion? Your review of the Putharjhora only mentions two infusions. If we cannot find one that yields three infusions, perhaps your theory about cultivating teas for British use (without resteeps) is correct.Scott Fnoreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-6241395879996685532012-04-09T09:24:56.599-04:002012-04-09T09:24:56.599-04:00Hmm...this has not been the case in my observation...Hmm...this has not been the case in my observations. Perhaps there has been a trend in this direction, but I can think of tons of examples to the contrary. Perhaps this could be related to the particular companies or sources from which you are getting your teas. For example, I regularly buy from Upton Tea Imports, and I think their strengths lie in Indian black teas.<br /><br />I recently tried a very interesting Darjeeling black tea from the Dooars (low-elevation) area, still in the Darjeeling district though, <a href="http://ratetea.com/tea/upton/to50-putharjhora-estate-ftgfop1-tippycl-first-flush-organic/5245/" rel="nofollow">Putharjhora Estate FTGFOP1 Tippy/Cl First Flush Organic</a>, from Upton, that performed extremely well under multiple infusions. I also recently tried a <a href="http://ratetea.com/tea/harney/singbulli-darjeeling-dj41/5518/" rel="nofollow">Singbulli Darjeeling</a> from Harney and Sons which performed better under multiple infusions than my average experience with black teas from China. I had a <a href="http://ratetea.com/tea/arbor-teas/makaibari-estate-darjeeling-1st-flush-black-tea/4332/" rel="nofollow">first flush Darjeeling from Makaibari estate</a> sold by Arbor Teas, which I also found to do well under multiple infusions.<br /><br />And I've certainly tried my share of Chinese teas that don't do well under multiple infusions.<br /><br />But, if there's a trend in this direction (even if I'm thinking up counterexamples to it) there's a plausible explanation I can think up, which is that the Indian teas were developed primarily for British tea culture, which tends not to infuse tea multiple times, in comparison to Chinese tea culture, which tends to do this (even for more casual tea drinking). This could have led to the selection of qualities in the tea (both through cultivar selection and production process) that would infuse very quickly, and be lost after the first infusion. In selective breeding and production of any food product, there is usually a tradeoff between different qualities, and if you're not selecting for a particular quality, it will often be lost as you select for other ones.<br /><br />I could add some of this to the article, but it seems a bit speculative and based on my personal opinion. I try to keep the articles on RateTea a little more objective and keep my opinions and speculative explanations over here on this blog. =)Alex Zorachhttps://www.blogger.com/profile/08335878680429494039noreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-41131994260863540222012-04-07T18:20:03.250-04:002012-04-07T18:20:03.250-04:00Here's a question that's been bugging me: ...Here's a question that's been bugging me: Why can you resteep Chinese black teas, sometimes as many as 4 or 5 times, but no Indian or Ceylon black gives even a remotely drinkable second steep? It makes good Chinese black teas seem like a bargain — and blacks from Assam and Darjeeling seem inferior, since even if they are whole-leaf and high-quality, it doesn't seem to make a difference for resteeping.<br /><br />I see you recently added an article to RateTea on multiple infusions, but it doesn't compare black teas. Any ideas?Scott Fnoreply@blogger.comtag:blogger.com,1999:blog-8825055425170299721.post-35876942570070857122012-04-05T13:37:47.849-04:002012-04-05T13:37:47.849-04:00Hi!
You might want to check out the caffeine and a...Hi!<br />You might want to check out the caffeine and antioxydant content of different at Camellia-sinensis.com (http://camellia-sinensis.com/health/virtues-tea/).<br /><br />Also, for analysis of tea chemical and antioxydant content compared to subjective tasting, I found that paper:<br />Ahmed S, Unachukwu U, Stepp JR, Peters CM, Long C, Kennelly E (2010) Pu-erh tea tasting in Yunnan, China: correlation of drinkers’ perceptions to phytochemistry. Journal of Ethnopharmacology 132: 176–185.Guillaumehttps://www.blogger.com/profile/04335164604591060707noreply@blogger.com