The long-term brewed, polyphenols and essential oils contained in tea, start to oxidize, which affects taste, color and flavor of the drink and reduces its nutritional value and destroys the vitamins.
And now scientists have named the time, which is optimal for tea brewing. It is exactly 3 minutes.
Tea put in the boiling water longer this time was researched by toxicologists. And they found in samples the heavy metals, in particular lead, aluminum, arsenic and cadmium. Researchers believe the metals came into the leaves because of the contamination of the soil, often because plantations are located near polluting coal-fired power plants.
How harmful substances can penetrate into your drink, depends on the time of brewing the tea. So if the bag is in the water for 15-17 minutes, the level of toxic substances rises to unsafe (for example, in some samples the concentration of aluminium amounted reaches 11 449 µg/l when the allowable daily maximum of 7 000 mg/l).
So you should not brew tea on the principle of “make and forget”, because 3 minutes is enough for a tasty beverage, and with each minute in excess of this, more and more unwanted substances penetrate into your Cup.