The Boiling Question
This week I stumbled on some research published in China on Jiaogulan. I almost overlooked it because the title was a bit misleading. The article title is “Determination of Rare Earth Elements and Active Substances in Wild Gynostemma pentaphyllum of Yongzhou and Their Releasing Law in Boiling Water”
I thought at first glance this was a study of rare earth elements in jiaogulan. While that interests me, the presence of rare earth elements in jiaogulan is very dependent on the area it is grown and since it was not a study of either of our jiaogulans I started to give it a pass.
But, out of idle curiosity I gave it a second look and it turns out to be such an obvious study that I’m surprised no one has done it previously. There is active debate about the best way to prepare jiaogulan tea for health purposes. Some practitioners boil jiaogulan for some time, while others insist on cold brewing as the best method to preserve the health benefits.
In this study, the researchers studied the concentrations of saponins, flavonoids and polysaccharides in gynostemma infusions prepared at a range of temperatures in order to develop a “releasing law” for the health beneficial compounds in jiaogulan.
The researchers found a direct correlation between water temperature and the concentration of beneficial compounds in the resulting infusion. In short, the hotter the water the healthier the tea. Actively boiling jiaogulan for 5 minutes resulted in nearly twice the concentration of beneficial compounds than steeping in boiling water and allowing to cool naturally and 4X as much than cold brewing.
So, case closed, boil your jiaogulan… whoa there little cowpoke! Not so fast.
Here are couple of things to think about.
First, this is classic scientific reductionism. We don’t know how to study nature in it’s full complexity so we try to take it apart and study one element at a time. I’m not convinced that the so-called “beneficial compounds” in isolation are as effective as the synergistic effects of the plant as a whole. (This is why I rarely advocate extract-type supplements). It could be that boiling the jiaogulan is destroying some beneficial compounds while more effectively releasing others.
Second, is the human factor is not considered. Bluntly, boiled jiaogulan tastes pretty awful. Only the most determined person will be willing to consume several cups of boiled jiaogulan tea per day. On the other hand, jiaogulan tea prepared at low temperature is mildly sweet and quite tasty. So, it may be that your consumption of beneficial compounds is higher drinking several cups per day of good tasting tea than choking down one or two bitter boiled teas.
I don’t think we yet have a definitive answer here without a clinical study. I know from my own experience that I feel the effects of jiaogulan more strongly after boiling. But I enjoy jiaogulan prepared at lower temperatures (or even cold brewed iced jiaogulan tea) a LOT better and am likely to consume it more often.
I recommend you try it both ways and feel what your body and preferences are.
Talk again soon,