My country is the birthplace of tea and the world's largest tea producer. Tea leaves are rich in a variety of medicinal ingredients, such as tea polyphenols, tea polysaccharides, alkaloids, etc. my country's tea drinking culture has a long history.
Many people like to brew a cup of tea every day, smell the fragrance of tea, and taste the tea, so many families have the habit of storing tea.
But why do some people say that the longer tea leaves are stored, the better? About the preservation of tea
How long can tea leaves be stored? Is it more fragrant the longer it is stored?
The shelf life of tea leaves is related to the variety of tea. Different teas have different processing techniques, and the storage time and the impact on them are also different.
① Green tea, the process is not fermented, and most categories also emphasize freshness. The shelf life at room temperature is generally about one year, which is not suitable for long-term storage. And the longer it is stored, the less fresh it will be, and the taste concentration will be much worse than before.
② Oolong tea, which is a semi-fermented tea, has a shelf life of about 18 months in the refrigerator. Those that have been roasted, such as Wuyi rock tea, can still be drunk after 2 years. The old tea of the previous year is fragrant and mellow in taste. Tieguanyin is also better if stored properly.
③ Black tea is a fully fermented tea, and it tastes best within three years.
④ Both white tea and black tea are worth storing. After a long period of transformation, the taste and quality will be improved. Especially for white tea, we have always said that "one year tea, three years medicine, seven years treasure". But this is under the premise of proper storage.
As for Pu'er tea, it is special. It is divided into raw tea and cooked tea. Generally speaking, the shelf life of raw tea is about 5 years, and it will become more fragrant as it is stored; the shelf life of cooked tea is more than 15 years, and the taste of the tea soup will be smoother as it is stored.
But it should be noted that any improper storage of tea will affect the taste and even deteriorate.
Can tea still be drunk after its expiration date?
In fact, the expiration date on the tea packaging bag or box is just an official reference number. To be more precise, it is the "best drinking period", which is when the tea aroma, taste and flavor are the best.
As for whether tea can be drunk, you can't just look at the expiration date. The more important thing is to see if the tea has "deteriorated".
How to identify whether tea has deteriorated
① Smell: Green tea has strong adsorption and hygroscopicity, and it is very easy to absorb some odors. If the tea has lost its original aroma and has a stale or moldy smell, it is best not to drink it.
② Look: The tea color is dark yellow, and the leaves are not "crisp", which is mostly deteriorated. Undeteriorated green tea is normally bright in color and has a water content of 7%, which can be rubbed into powder.
③ Soak: Take some tea leaves and soak them for a while to see if its soup color is pure and whether the concentration of the tea soup has changed. If the tea soup becomes turbid, it is not suitable to drink it.
The factors that affect the quality of tea are mainly temperature, light, and humidity. Reducing or eliminating these factors can better ensure the quality of tea.
Although tea is good, it is not omnipotent
There are many nutrients in tea, so there are many rumors about its effects on the Internet:
Can drinking tea fight cancer?
In recent years, there have been many news about drinking tea fighting cancer.
Cell and animal experimental studies have shown that although tea polyphenols have a certain preventive and control effect on lung cancer and colon cancer, there is still a lack of convincing direct evidence in humans.
In addition, there are many active ingredients in tea, but the content is limited. It does not mean that drinking tea alone can prevent cancer.
Can drinking tea sober up?
Tea has the effect of refreshing the mind, so many people think that drinking tea can sober up, especially drinking strong tea, which has a better effect.
In fact, strong tea not only does not sober up (sobering up mainly depends on enzymes), but also hurts the kidneys.
Theophylline in strong tea can quickly produce a diuretic effect through the kidneys, which will cause acetaldehyde that has not yet been oxidized to enter the kidneys prematurely. Acetaldehyde is highly toxic to the kidneys, which can damage the glomerular and tubular cells and cause harm to kidney function.
Can tea remove formaldehyde?
Tea has a certain adsorption effect, so many people use it as a refrigerator deodorizer, and some people put a lot of tea in the new house to remove formaldehyde.
But in fact, the effect of tea on formaldehyde is only physical adsorption, and the absorption effect is minimal. Tea only covers up the smell of formaldehyde, which does not mean that the air is truly purified.
Ventilation is the most direct and affordable way to remove formaldehyde, using the flow of indoor air to reduce the content of indoor pollutants.