Why does it get dark in the morning after a night of tea water?

It is the cause of oxidation.

The main change is tea polyphenols.

of further oxidation, color deepening. A cup of clear and turquoise tea, especially if left for a long time in high temperatures, will lose its green color and increase the degree of yellowness. This is the oxidation product of the oxidation of tea polyphenols in tea to form yellow-red and reddish-brown, mainly theaflavin, thearubigin, theabrownin, etc.

These products are non-toxic and do not cause harm to the human body.

Overnight tea. Special Uses.

1. Overnight tea is rich in acids and fluoride, which can not only prevent capillary bleeding, but also play a role in sterilization and anti-inflammatory.

2. If there is red silk in the eyes or tears for unknown reasons, it will have a good effect if you use overnight tea many times a day.

3. Wash your hair with overnight tea to treat itchy scalp.

That's due to the presence of tannins in the tea leaves, which chemically react with the iron ions in the iron pot, resulting in a black color. When the new iron pot is boiled for the first time, the food will be stained black, so you can use tofu residue to rub the pot a few times to avoid contamination.

After each meal, the inner wall of the pot must be washed and wiped dry to prevent the pot from rusting and producing iron oxide that is not good for human health. For iron pots that are seriously rusty, black slag, and black skin, they should not be used again.

If the tea turns black and the stove is destroyed, it is likely to be caused by factors such as the quality, type, production method, storage method and water quality of the tea. Here's why:

1.The quality or type of tea is not good: the choice of tea or the type of tea will affect the color of the tea, for example, the color of the tea leaves on the old tea trees in some mountainous areas is darker, and the tea leaves of the camellia dragon are more slender and dark, especially the low-priced tea leaves are prone to dark color.

2.Different production methods: Different production methods and processes will also produce different colors. For green tea, the production process will be roasted, if the temperature of the roasted green is too high or too long, it will cause the color of the tea leaves to be darker.

3.Improper storage: During storage or transportation, if the tea leaves are exposed to the sun or moisture, the tea will lose its nutrients and become dull in color.

4.Influence of water quality: Water quality is an important factor affecting the blackening of tea, if the water quality is not good, the tea is easy to turn black. If you use water containing minerals such as calcium, iron, and manganese to make tea, it is easy to cause the tea to turn black.

Therefore, when we make tea, we should choose high-quality tea leaves, pay attention to water quality and storage conditions, so as to ensure that the brewed tea has a fragrant taste and bright color.

The tea leaves contain tannins, the astringency of the tongue, and the chemical reaction between it and iron ions produces a black color, which is the reason why the tea leaves boiled in the new iron pot turn black. Sakura shoots oranges.

Because the surface of the old iron pot has been covered, the tannins have not been in direct contact with iron ions, and the water has not turned black for a while, and it has become black after a long time.

Tea generally refers to the leaves of the evergreen shrub tea tree that can be used to make tea, as well as the drinks brewed from these leaves, and later extended to all herbal teas brewed with plant flowers, leaves, seeds, and roots, such as "chrysanthemum tea"; "Herbal tea" made with various medicinal herbs, etc., is also known as thunder buds in Chinese literature. In some countries, there is also tea made from the leaves of other plants such as fruits and herbs, such as "fruit tea".

Tea leaves contain tannins, astringency felt by the tongue, and it reacts with the chemical anti-rent of iron ions to produce blackness, which is the reason why the tea leaves boiled in the new iron pot turn black.

The old iron pot has a layer of covering on the surface of the old iron pot, and the tannins have not been in direct contact with the iron ions, and the water has not turned black for the time being, and it has become black after a long time.

Tea generally refers to the leaves of the evergreen shrub tea tree that can be used to make tea, as well as the drinks brewed from these leaves, and later extended to all herbal teas brewed with plant flowers, leaves, seeds, and roots, such as "chrysanthemum tea"; "Herbal tea" made with various medicinal herbs, etc., is also known as thunder buds in Chinese literature. Some countries also have tea made from the leaves of other plants such as fruits and herbs, such as "fruit tea".

The black tea may be mildew or inferior black tea, and the soup color of high-quality black tea is red, clear and bright.

How to choose a good tea leaf:

1. Hand grasping: First of all, use your hands to feel the weight, tightness and thickness of the black tea cord. The cords of high-quality black tea are relatively tight, and the heavy ones are better, and the rough ones are inferior to those that are coarse and light.

The main purpose of touching the tea leaves with your hands is to understand the dryness of the black tea dry tea. Take a tea strip at hand, dry tea usually has a prickly feel, easy to break, and rub it vigorously with your fingers to become a powder. If it is a damp tea leaf, it does not have this characteristic.

However, when touching the tea leaves, do not scratch them to avoid the sweat on your hands from seeping into the tea leaves and causing the tea to get wet.

2. Eyesight: Grab a handful of dry tea and put it on a white paper or white porcelain plate, hold the plate in both hands to quietly needle or rotate in the direction of clockwise or counterclockwise, and observe whether the shape of the black tea and dry tea is uniform, whether the color is consistent, and some also need to see whether there is a golden quill. The cord is tight and clean, no seepage to search for broken tea or less broken tea, and the color is black and oily (some tea will also show golden hair) is preferred.