Do not drink overnight green tea!
There is the teaching that the green tea which you put overnight must not drink in Japan from old days.
The following is a review of the people who actually drank it.
“I am scared the spiciness that was not in the past“
“Do not drink green tea that you put overnight” is true. I have a stomachache.
“When I drank green tea that I put overnight there was a texture, it seems rotten … and I can not vomit..“
Apparently, the green tea leaves that were left overnight rot, and it seems that bad ingredients will appear in the stomach. It seems to cause food poisoning and indigestion. However, green tea should have catechins bactericidal action. Then why does it rot?
Actually, it is because tea leaves contain unexpectedly perishable protein. Green Tea leaves contain a lot of tannin (catechins) with excellent bactericidal activity, but also proteins that are prone to spoilage. In addition, about 100g of protein in tea leaves is abundantly contained in about 30%. Moreover, the catechins with disinfection effect has flowed out of the used green tea!
Yes, the green tea leaves that have lost their catechins have only decaying elements. When green tea is made, water-soluble catechins will dissolve into the tea’s liquid, but the protein remains in the tea leaves because it is not soluble in water (hot water).
As the number of catechins in the green tea leaves decreases as the second and third deconstruction proceed, the protein will eventually spoil and cause food poisoning etc.
There is a catechins and small amount of protein in the first tea and second tea. So it seems to be OK even if you put it overnight and drink.
In addition, catechins left to the green tea leaves changes the ingredients which are bad to stomach by being oxidized. Green tea contains many active ingredients such as catechins. however, as these components are oxidized over time, they turn into substances with strong irritant. The taste of overnight green tea is strange bitter, it’s because tannin came out too much in the tea.
Appropriate amount of tannin stimulates cells of the stomach (such as parietal cells and main cells) to promote secretion of gastric juice and help digestion of food.
However, if the amount is too much, the mucous of the stomach will be roughened, it will interfere with the secretion of digestive juices, causing dyspepsia, people with weak gastrointestinal symptoms may cause nausea and diarrhea. Overnight green tea causes food stuffiness caused by decay of tea leaves, as well as roughness of gastrointestinal tract. People of old days knew this from experience.
And wow! Apparently the ninja made poisons with neglected green tea long time ago!
Let’s store green tea in the refrigerator if you really want to overnight. We propose a method of drain off the water from the tea leaves which was made in the morning,putting it in a plastic bag with a teapot,sealing it ,and store in a refrigerator.
Read related article to learn more about preservation measures
Quoted from https://matome.naver.jp/odai/2139816400033292001