Bagged tea is best brewed only once
Loose tea should not exceed 3 brews
How many times should tea leaves be brewed to be most nutritious and healthy? Many people are unclear about this.
Some people like to steep tea leaves repeatedly until no flavor remains. Others change tea leaves after just one or two brews. Which approach is correct? How many times should a cup of tea be brewed? Yin Junfeng, associate researcher at the Tea Research Institute of the Chinese Academy of Agricultural Sciences, says that while the number of brews relates to personal taste, from a nutrient absorption perspective, bagged tea is best brewed only once, while loose tea shouldn't exceed three brews.
He explains that tea contains cancer-inhibiting tea polyphenols, blood-sugar-lowering tea polysaccharides, central nervous system-stimulating caffeine, and various amino acids and vitamins. How much of these nutrients are released depends greatly on brewing frequency. Generally, larger tea particles release nutrients more slowly; smaller particles release them faster.
Compared to loose tea, bagged tea leaves are cut and rolled during processing, thoroughly breaking leaf cells and creating smaller particles. During the first 3-5 minute brew, 80-90% of nutrients are released. After the second brewing, the remaining 10% of nutrients are almost completely released. Therefore, Yin Junfeng recommends brewing bagged tea only once - this doesn't significantly impact nutrient absorption nor affect taste and flavor. Loose tea, with larger particles, requires longer first brewing (about 5 minutes), releasing 60-80% of nutrients; the second brew releases 80-90% of nutrients, and the third brew releases over 95% of nutrients. Further brewing provides little nutritional benefit.
Regarding expert concerns that multiple brewing could leach pesticides and heavy metals from tea leaves, Yin Junfeng says while there's some truth to this, excessive worry is unnecessary. Currently, most pesticides used in Chinese tea production have extremely low water solubility. Even brewing tea with 1 mg/kg pesticide residue, consuming 10 grams daily would intake only 0.0001 mg of pesticides - several thousand times less than the WHO's daily allowable intake. The leaching rate of heavy metal lead from tea is also relatively low. As long as you purchase from正规 manufacturers, the content won't exceed national standards.