Some people prefer to use a tea cup to brew and drink light tea, while others use a glass cup to brew and enjoy strong tea. Although the number of times tea leaves are brewed and personal taste preferences vary greatly, from a nutritional absorption perspective, bagged tea is best brewed only once, while loose tea should not exceed three times. He explained that tea leaves contain tea polyphenols, which have cancer-suppressing effects, tea polysaccharides that can lower blood sugar, caffeine that stimulates the central nervous system, as well as various amino acids, vitamins, and other nutrients.

Compared to loose tea leaves, the leaves in bagged tea are cut and rolled during processing, which thoroughly breaks down the leaf cells, resulting in smaller颗粒形状. During the first 3-5 minutes of brewing, 80%-90% of the nutrients in the tea are released. After the second brewing, the remaining 10% or so of nutrients are almost entirely released. Bagged tea is best brewed only once, as there is no loss in nutritional absorption, and it does not affect the taste and flavor.

Due to their larger颗粒, loose tea leaves require a longer brewing time for the first infusion—about 5 minutes—during which 60%-80% of the nutrients are released. After the second brewing, 80%-90% of the nutrients are released. After the third brewing, the leaching rate of nutrients exceeds 95%, and further brewing has little nutritional effect. Therefore, it is scientifically justified not to exceed three brews for loose tea.

As for experts pointing out that multiple brewings can leach harmful substances such as pesticides and heavy metals from tea leaves, this statement has some truth but need not be overly worried about. Currently, most pesticides used in tea production in China have very low water solubility. Based on drinking 10 grams of tea per day per person, even brewing tea with 1 mg/kg residue would intake only 0.0001 mg of pesticide, which is a fraction of a thousandth of the daily intake allowed by the World Health Organization. The leaching rate of heavy metals like lead in tea is also relatively low. As long as you purchase tea from正规厂家, their content will not exceed national standards.