Any Health Benefits in the Tealeaves after First Infusion?
Infused leaves of a Phoenix oolong: Shiguping Wulong
Can I use the same tealeaves for a couple of infusions? I mean, I read in some places that it’s ok, but I don’t know if there will be any health benefits after the first infusion. Any tips?
A question from reader Kate
Although I think the reason for another cup of tea is more for its quenching quality and fine taste, the salutary nature in every sip is somehow unmistakably part and partial of the whole deal. Before the right tea selection strikes the gastronomic senses of a drinker, the health supplements dissolved in that hot water need to be strong enough to convince the next sip.
Caffeine, for example
Of the few major tea substances that we are most concerned with, caffeine is the most readily water-extractable one. Let’s look at it to illustrate the idea. In a study in Auburn University in the US (1), where 8 commercial tea samples were infused repeatedly for 3 times, each time for 5 minutes, it was found that an average of 68% (2) of the total caffeine came out into the water in the first round. 23.6% came out in the second.
There were two teabag selections in the samples. We all understand that substances in the dusting in that “non-woven fabric” come out a lot more readily because of the tiny particle size of the debris of processed tealeaves. If we look at their figures alone, almost 74% of the content would come into water in the first round and 20% in the second. That may also explain why a second round from a teabag doesn’t taste well.
If we disregard the teabag figures, the percentage would be 65.8% and 25.1% for the leaf tea samples, though it was unclear whether those were only broken leaves. I guess quite possibly they are, considering what one can get normally in US.
What about tea catechins, the most highlighted health content in tea?
Similar meaningful studies are rare. In a study jointly conducted by 3 major universities in Taiwan (3), where eight leaf tea samples were freshly grounded and put into teabags to repeatedly steep for 8 times each for 30 seconds ( most people steep their teabags for an average of 8 seconds ), the way the tea contents came into water was a lot more gradual. Take EGCG for example, in the green tea samples infused at 85°C — they studied also the effects of water temperature — about 12mg per g of tealeaves came into water in the first round, 10 in the second, almost 9 in the third.
Health substances dissolved in subsequent infusions
Freshly grounded whole-leaf green tea (Jinxuan) infused in 85°C water for 30 seconds in each round of infusion.
Y-axis reflects the number of mg of the content dissolved in water per gram of tealeaves. Data source as in note 3. This chart involves only much simplified datas from the report to illustrate the point.
Breaking the whole leaves into the same particle size as tea dusting in a bag speeds up the infusion process dramatically, although it is unknown by how much. Perhaps infusing such broken leaves for 30 seconds is equivalent to 3 min for the whole leaves?
Let’s first follow the findings of the research. To understand it, first we have to understand that most catechins and other tea polyphenols infuse into water more slowly than caffeine. That is not only because of the relatively less dissolvable nature of the molecules than caffeine, but also because caffeine crystals tends to surface during production processing in most teas that are rolled, curled or twisted. That is why you see almost the identical amount of caffeine and EGCG in the first infusion in the chart, although there is less total caffeine than this most potent of all catechins in the samples.
Therefore, if you disregard caffeine as a health substance ( though this is highly arguable ), it is indeed more true that a significant percentage of health substances are still in the tealeaves after the first infusion.
None reports, however, reflects the real environment in which leaf tea is infused.
Teabags
20% of the caffeine can still be extracted in the second infusion in a teabag.
Often if we use a teabag, however prestigious brand it is, we often find it almost tasteless after the first infusion. That is because there is not much to start with (4). The total surface area of these broken leaves ( at best, most are only dustings or fannings ) is relatively so much greater than that of whole leaves that it simply invites much quicker oxidation and other forms of degradation. Packing these tiny grains in 2~3 g in small bags further increases the surface area. This is further worsen by the popular use of flimsy outer packaging — those thin cellophane and thin paper cartons are ridiculously feeble when you compare how other better products are packaged.
A lesser tea to start with, chopped up, surface area further increased by packing into tiny portions, and extremely poorly insulated from the environment in transportation, warehousing and the fluctuating humidity and temperature of the store, these much compromised form of tea is hardly representational of the original nature of the beverage (5). That is why even there are measurable figures in the US findings, empirically we find it not convincing.
That is to say, if you are using commercial teabags, you can forget about second rounds. 20% of nothing much is nothing.
Leaf tea
When you use leaf tea, however, it is a very different story, especially when it is whole leaf. It is easy to understand that with short infusions, that is particularly the case. What about standard 5-minute ones?
Take our daily tea sample tasting experience as a reference. Our standard infusion time for all initial tasting is always set between 5 to 6 minutes. When some teas are really good, we normally keep them for a second round to share or to put aside as any other tea for drinking. Most of the times these second rounds come out highly enjoyable. When there are taste substances, there are health substances. They are the same thing most of the times.
What we do as tasters
The question Kate sent us seems to relate more to conventional long infusion practice rather than gongfu style. You won’t dump the leaves even after the 3 rounds if you practice shorter infusion duration with whole leaves anyway. So let’s see the answer for those who steep their whole leaf teas for at least 5 minute.
In my studio, for general tasting we use 150ml taster’s mugs and 3g of leaves to each mug. As the concentration of the tiny bit of tea liquid goes up during that 5-minute, osmosis slows down, temperature of the whole mass drops, the infusion effectiveness drops. Lots of contents are reserved in the leaf tissues for a second round.
If you infuse the same amount of leaves filling up a bigger pot, say 350ml, the picture would be a bit different, but still there is much for second round. As in the US study where they do 5 minute infusions and 1g to 100ml water, it is 25%.
The difference of tea varieties
One key factor that none reports cover is the difference between various tea categories. By experience we all know that certain pu’ers and oolongs, particularly Phoenix and Wuyi oolongs, are still very good in the second infusion, even when we use the conventional 1 to 100 proportion and 5 min approach. Not so for most green, white and black teas. I guess there is a lot more than 25% waiting for us in the second round of a Milan Xiang Dancong ( Honey Orchid ).
An explanation for this may be related to the structure of the leaf tissues in the plucks for processing the different tea categories. Usually the leaves are much tougher in the case of the traditional oolongs and some pu’ers. That has to do with the difference in both the timing of the harvest and the cultivars involved.
In practice, I dump that 25% in the white, green and black tea and always reserve the oolongs and puers for at least a second go, in those time that I do long infusion. To me, Life is too short for just 25% of something good.
