Does Black Tea Astringency Really Cause Stomach Pain?
Stomach pain after drinking black tea or raw Pu-erh is usually not caused by the tea category itself. The more likely source is the picking season: summer tea accumulates a compound that makes the leaf strongly astringent and irritating to the stomach, and any tea made from that fresh leaf, regardless of type, can produce the same discomfort.
First spring flush leaf is the opposite: sweet, smooth, and delicate, with almost no astringency, so it sits easily even on an empty stomach. Heavily roasted oolong or ripe Pu-erh made from summer leaf shows far less astringency. The same logic behind black coffee in cough discussions applies here: processing and raw material decide the effect, not the label.
Many consumers avoid black tea or raw Pu-erh due to stomach discomfort, but the problem may not lie with the tea category itself. This article combines tea picking seasons, research on astringent compounds, and scientific literature to reveal the true sources of black tea astringency and stomach irritation. At the same time, we will explore the potential benefits and side effects of black tea, and explain why first spring flush tea is gentler on the stomach. If you have ever experienced stomach pain from drinking tea, or want to know how to choose a black tea that does not upset your stomach, the perspective offered in this article may help you find the answer. Front Street Coffee will also, from a professional angle, sort out the key points for choosing and tasting tea for you.
We have noticed that quite a few customers avoid black tea or raw Pu-erh because of stomach discomfort. I myself have had the same experience, developing stomach pain after drinking black tea. But in fact, this is not necessarily connected to black tea or raw Pu-erh themselves. If the tea raw material is inappropriate, any tea category can trigger similar discomfort. Conversely, if suitable raw materials are used, even on an empty stomach, we can safely enjoy all kinds of tea.
The problem often comes from tea picked in summer
According to our observations, summer tea is strongly astringent and easily causes stomach pain. In warm seasons, especially summer, a special compound accumulates in tea leaves. No matter which type of tea this fresh leaf is made into, the taste tends to be astringent and may irritate the stomach. For the same reason, Darjeeling summer-picked tea also carries a pronounced astringency. If the tea is processed into ripe Pu-erh or heavily roasted oolong, the astringency becomes almost negligible.
I have had similar experiences with natural herbs. In Japan, I often go into the mountains to gather wild herbs. In spring, these herbs are sweet and rich in flavor. They can also be gathered in summer, but they become very bitter and difficult to enjoy.
To make black tea or raw Pu-erh, the best-quality raw material is the fresh leaf from the first picking in early spring. Usually, first spring tea tastes sweet and smooth, with a delicate and soft texture, and absolutely no astringency. However, common black tea and raw Pu-erh on the market mostly use fresh leaves picked in late summer. Tea from the second and third pickings has reduced delicacy and softness, but is still acceptable. After the fourth picking, the astringency becomes very obvious.
In China, the price of first spring tea is twice that of second-picked tea, while third- and fourth-picked tea is much lower. Due to strong demand, the output of first spring tea is extremely limited. Famous tea regions can pick tea more than ten times a year, which means the chance of first spring tea is less than one in ten. Considering the huge domestic demand for first spring tea, most black tea or raw Pu-erh available abroad is late-picked tea. This is exactly why many people have negative experiences after drinking black tea or Pu-erh. If first spring tea is used, there is completely no astringency, and the irritation to the stomach is very mild. No matter how strong it is brewed, even drinking it on an empty stomach is fine.
The root cause of astringency
The question now is what substance in tea causes stomach pain and astringency. If we investigate which component is especially abundant in summer tea, we should be able to find the answer. I found relevant data on page 22 of the Japanese book The Science of Tea by Sadamu Yamanishi. The results show that after summer arrives, the content of epigallocatechin gallate (EGCg) rises significantly.
They monitored four different teas. From left to right, number one is the Yabukita cultivar, number two is Qingxin Oolong, number three is Hongyu, and the last is an Assam cultivar from Sri Lanka. "Spring" represents spring, and "Summer" represents summer.
Another paper, B Schwarz, T Hofmann - European Food Research and Technology, October 2008, 227, explains in its abstract that epigallocatechin gallate has a strong binding ability with proteins.
Susanne Scharbert, Nadine Holzmann, Thomas Hofmann, J. Agric. Food Chem. conducted sensory research on the substances in tea that cause astringency. The table below shows the taste thresholds of various polyphenols. The data indicate that epigallocatechin gallate has the strongest astringent effect. Based on these materials, we can conclude that epigallocatechin gallate is the substance that triggers the sour and astringent sensation in the stomach.
The mechanism by which EGCg causes astringency
Our oral cavity and stomach cavity are made of proteins. If a substance binds to the protein layer, it produces astringency and discomfort. Tea with milk added has the least astringency and the least stomach irritation, because epigallocatechin gallate has already reacted with milk proteins and is no longer active.
In summary, the astringency of tea or stomach discomfort is unrelated to processing techniques or tea category, but is directly affected by the raw material. If first spring tea is used to make it, we will not taste any astringency, nor will we have stomach pain.
The above content is compiled by CoffeeHunters, a coffee news website.
