I was recently given a magazine article about a scientific study showing that oolong tea aids weight loss. Woo hoo! Of course, the scientist in me had to take a closer look…
The Good News: According to the article, rats prone to weight-gain were divided into two groups, and the ones that were given food laced with tea (dried extract of brewed tea) gained about 2/3 less weight than ones who had normal food, despite eating roughly the same amount. The “tea mice” who got 4% of their food intake as tea extract gained 20 grams, and those who got 2% of intake as tea gained 20 grams, while the “non-tea mice” gained roughly 120 grams each. The 2% dose in a human would be roughly 6 cups of strongly brewed tea per day. It’s thought that substances from tea leaves called saponins change how the body takes in fat, or the fats themselves, so the body doesn’t absorb as much.
The Bad News: First, a human drinking 6 cups of strong tea may well be different than a rat eating extract of brewed tea. While I’d love to use this study as an excuse to recommend anyone over average weight to drink six cups of tea a day, I’d like to see some kind of human study, or one showing that the action of tea saponins works the same way chemically in a human gut as it does in a rat gut.
Second, although I found more information about the study from the magazine’s website including the title (“Oolong tea reduces food intake, body weight, and body fat in spontaneously obese rats”), I couldn’t find any references to the study outside of the magazine’s site and a couple of blog posts in an admittedly fairly quick search. Apparently, the study was reported at the Experimental Biology ’07 meeting, and may not have been actually published. I did a search for the authors and didn’t find anything about the primary author, and a CV of an “et al” author that didn’t list this study under her “selected publications.”
Of course, this doesn’t mean the study doesn’t exist, but it makes it hard to evaluate the study if you can’t find the study that you’d like to evaluate. However, it is interesting in that it offers data connecting tea with weight loss as well as the mechanism by which it might work. (Previous to reading the article, I had always assumed that any weight loss from tea drinkers versus non-tea-drinkers was probably due to caffeine speeding up the body a bit and thus burning a bit more energy.)
A news story from the English language version of Xinhua (China’s news agency) on today’s earthquake near Pu-er, which gives its name to fermented teas worldwide.
Yesterday morning I got an email from one of my personal tea gurus. It included a list of the tea books in his own library (including title, author, publication information, etc.)
The list covered 208 books.
It had everything from Novelty Teapots: Five Hundred Years of Art and Design and Afternoon Tea Cakes, Tasty Sandwiches and Sweetmeats to the entire opposite end of the tea-book spectrum (if there is such a thing) with volumes like The Effect of Plant Mineral Nutrition on Yield and Quality of Green Tea (Camellia Sinensis L.) Under Field Conditions and Specification of HDPE Woven Sacks–A New Alternative Packaging Material for Tea.
Holy crap I’ve got a lot to read…
Friday I sat down with Shiuwen and David at Floating Leaves Tea to taste teas from Ali Shan (阿里山) that Shiuwen had just brought back from Taiwan. We tasted it in the method of Taiwan tea buyers–leaves loose in a bowl, with a spoon to dip, smell, and dish out a sample into your own cup. This method allows a taster to see the development of a brew over time, instead of just at a particular moment when the tea timer goes off.
Let me start by saying they were all wonderful lightly-oxidized, rolled oolongs. Like most teas of this type, the flavor was somewhat green and vegetal with a hint of floral. But even though all four came from Ali Shan, they each had their own character.
- Ali Shan Ding Hu (about $11/ounce). This is from a new growing area on the mountain around 1700 meters in altiutde. My first impression was that it had a sugary taste to it–not necessarily the sweetness of fruit, but like the high clear flavor of granulated white sugar. Good flavor, smooth, great aroma. (When I smelled the dry leaves the first time I recoiled a little–in a good way–because it was surprisingly heady.)
- Ali Shan Lao Jizi “A” (about $24/oz.). This was the king of the hill, so to speak. It stood up to the water very well, and David pointed out to me a hint of citrus flavor in with the more vegetal taste of tea. At first, I found it to be like the citrus of lemon juice, but as the tea continued to steep, it became more like citrus zest. It had what I’ve been told is called “labduz” in Persian: a mild and pleasant astringency.
- Ali Shan Lao Jizi (about $17/oz). This tea is a more every-day production from Lao Jizi’s farm. It was a little more oxidized and a little more strongly roasted, both of which combined to make it fruitier than the others. It reminded me ever so slightly of the crust of blackberry pie (last year’s Dong Ding from Floating Leaves strongly reminded me of fruit pie crust). Shiuwen said it reminded her of last year’s Da Yu Lin. While this might not have been the highest quality possible, it was my favorite based on flavor.
- Fragrant Ali Shan (about $10/oz). The Fragrant Ali Shan was true to its name, producing a lovely fragrance. In comparison, however, the flavor was a little more woody/roasty than I had expected. Perhaps it was because of the longer-than-usual stems included with the leaf. While we tasted these, a customer came into the shop, bought this tea to drink, and said they loved it.
In this, my first Tea Geek blog post, I want to tell a story about how brewing matters. I have a part-time “day job” at the Perennial Tea Room in Seattle’s Pike Place market. People ask all the time if it really matters what kind of pot you brew in, or how hot the water is. This is my story about why the answer to this question is “yes.”
We got samples of the spring 2007 pickings of Baozhong (包種) and Jinxuan (‘golden lily’). Four days ago, I weighed a pennyweight of each tea and brewed it in the standard tea industry brewing cups for five minutes each at 175 degree water. The result was extremely light and not very interesting at all. I left the Baozhong in the water for another five minutes to see if that would make a difference. It didn’t much–although it did develop a slightly more typical baozhong flavor, it was still VERY light.
Next, I brewed them in a small Chatsford pot with water at 175 degrees, again for five minutes. The result? Same as the first time. So we called our vendor and asked “what’s up?” (Tea does take some time to “settle in” when it gets to a new home, so we asked if it might be brewing light because our samples had just touched down the day before.) We were told to try brewing in a gaiwan (Chinese lidded tea bowl/cup) with hotter water.
Yesterday, we tried the Jinxuan with the recommended vessel and water temperature (4 grams of tea for 4 ounces of 195-degree water, 5 minutes). The difference was huge–the flavor was wonderful and we were able to give 4 or 5 serviceable brewings out of it.
My theory (since the international standard brewing cup, the Chatsford pot, and the gaiwan are all glazed porcelain) is that the primary difference was the water temperature in the vast difference between the Monday and Thursday brewings.
…and welcome to the Tea Geek blog!