Many people have such a memory in childhood: when they were children, they saw their grandfather's teacup, which summarized a thick layer of tea scale, and the old people would always solemnly say that tea scale is a good thing, no need to pour tea, pour some boiled water to have the taste of tea. If you clean his tea dirt, you often get a chase.
However, in recent years, there have been more and more theories about the harm of tea scale, such as some people say that tea scale retains a large number of heavy metals, nitrite, if not cleaned in time will cause cancer, and even some people made up a smooth mouth, "drink tea without washing the cup, Yan Wang urges his life."
So, what exactly is the composition of tea dirt on a teacup? Does it really harm our health?
Regarding the formation of tea scale, some people once believed that it was calcium carbonate or magnesium carbonate that adsorbed thearubigins, theaflavins and other substances in tea after precipitation; It is also believed that the floating matter on the surface of the tea soup is the wax on the surface of the tea leaves.
In fact, the main component of tea scale is tea polyphenol polymer, in addition, a small amount of metal ions are involved.
Researchers from Nanjing Agricultural University have done experiments on the effect of tea leaves with different degrees of fermentation on the formation of tea scale, and found that in the total amount of tea polyphenols, green tea> yellow tea> green tea > black tea, while tea polyphenols were positively correlated with the amount of tea scale of tea raw.
Therefore, green tea with the highest content of tea polyphenols is more likely to form tea scale, while black tea with a higher degree of fermentation produces relatively less tea scale.
In addition, calcium ions are a key element in the formation of tea scale. Experiments have shown that pure water brewed tea tea scale will be much less, while tap water is easy to breed tea scale, groundwater hardness is greater than surface water, so the more "hard" the water is, the more tea scale.
After elemental analysis, it is shown that the composition of tea scale is mainly carbon and oxygen, and there are also a small amount of potassium, calcium, magnesium, aluminum, zinc, selenium and other elements, while heavy metal pollutants such as lead, arsenic, cadmium, etc. are not the main metal elements of tea scale, so they will not constitute a health hazard.
However, since tea scale is a polymer of tea polyphenols under the action of air oxidation, the longer the time, the greater the molecular weight of the polymer, so the longer the tea scale exists, the more difficult it is to clean.
Also, when we look at the tea soup of overnight tea, we will find that there is an oil film on the surface, and many people say that this is a heavy metal, in fact, this statement is also nonsense.
Because the tea scale deposited in the tea soup will not immediately release heavy metals into the tea soup, and the main component of this oil film is also tea polyphenol polymer, which is basically the same as the tea scale component.
All in all, the harm of tea scale is not as alarmist as the rumors, and tea lovers can rest assured.
However, tea scale has been attached to the tea cup for a long time, which is indeed unsightly, just like a person is not trim, so we still have to clean it regularly.
When cleaning tea scale, you can choose special detergents, sodas, etc., in addition, clay tea sets with tiny pores such as purple clay pots have strong adsorption power, and tea scale will be absorbed by pores, so we must also clean in time.